The virulence of Dichelobacter nodosus, measured by the elastase test, is an important predictor for virulent footrot diagnosis in New South Wales sheep flocks.

Ovine footrot is a contagious bacterial disease that causes foot lesions, and depending on the virulence of the causative strains, may lead to severe underrunning of the hoof and lameness. Virulent footrot can be identified, treated and controlled more effectively than less virulent benign forms. The in vitro elastase test for virulence of the causative bacteria, Dichelobacter nodosus, has been used to support clinical diagnosis. However, not all laboratory-designated virulent D. nodosus strains cause clinical signs of virulent footrot. This study evaluated retrospectively how well the elastase test supported clinical footrot diagnosis in 150 sheep flocks examined for suspect footrot in New South Wales between August 2020 and December 2021. Flocks were included if measures of clinical disease, environmental conditions and the virulence of D. nodosus isolates were available. Variation in the elastase activity result between D. nodosus isolated from the same flock made bacterial virulence hard to interpret, but calculating the mean elastase rate for all isolates from the same flock made correlations between bacterial virulence and flock footrot diagnosis possible. Simplifying bacterial virulence into whether there were any elastase-positive D. nodosus isolates before 12 days increased the predictive value of elastase results for virulent diagnosis, compared with using the first day that any isolate was elastase positive or the percentage of elastase-positive isolates by 12 days, but not all clinically virulent flocks had isolates with elastase activity before 12 days. Logistic regression models were fitted to identify the minimum number of predictors for virulent footrot diagnosis, with models suggesting that virulent footrot diagnosis was best predicted by adding the elastase test result and environmental conditions to the prevalence of severe foot lesions (score 4 and 5). However, performing the same analysis with different breeds, ages of sheep and seasons might highlight other factors important in the diagnosis of virulent footrot.

The clinical and laboratory impact of reporting faecal elastase-1 in watery stool samples.

BACKGROUND: Low faecal elastase-1 (FE-1) results are suggestive of pancreatic insufficiency, but watery diarrhoea may lead to falsely low results. METHODS: FE-1 results reported on watery samples over a three-year period were reviewed. Results in watery samples were compared to those from a formed sample. The follow-up of patients in whom an FE-1 result ≤199 ug/g stool (Schebo ELISA) was reported on a watery sample was also reviewed. RESULTS: In total, 288 watery samples were identified. All results (19/19) ≥200 ug/g in watery samples were also ≥200 ug/g when measured in a formed sample from the same patient. There were 41 results ≤199 ug/g in watery samples, of which 29 (71%) were ≥200 ug/g when measured in a formed sample. Thirty-seven patients with a single FE-1 value ≤199 ug/g from a watery sample were followed up. Pancreatic Enzyme Replacement Therapy (PERT) was commenced in 15 patients. This was inappropriate in at least one patient. Reporting practice was subsequently changed to not report FE-1 values ≤199 ug/g in watery samples. This change was assessed after 12 months. Repeat samples were received from 15/56 (27%) of patients. Overall, 10/15 (67%) of samples were ≥200 ug/g on repeat. PERT was not commenced inappropriately in any of these patients. CONCLUSIONS: There is value in measuring FE-1 in watery samples, as 144/288 (50%) of watery samples analysed were ≥200 ug/g, enabling a diagnosis of exocrine pancreatic insufficiency to be excluded. Not reporting FE-1 values ≤199 ug/g in a first-time watery stool samples appears clinically safe and has potentially reduced inappropriate diagnoses and prescribing.

Therapeutic Potential of Antimicrobial Peptide PN5 against Multidrug-Resistant E. coli and Anti-Inflammatory Activity in a Septic Mouse Model.

Antibiotic-resistant bacteria have become a public health problem. Thus, antimicrobial peptides (AMPs) have been evaluated as substitutes for antibiotics. Herein, we investigated PN5 derived from Pinus densiflora (pine needle). PN5 exhibited antimicrobial activity without causing cytotoxic effects. Based on these results, we examined the mode of action of PN5 against Gram-negative and -positive bacteria. PN5 exhibited membrane permeabilization ability, had antimicrobial stability in the presence of elastase, a proteolytic enzyme, and did not induce resistance in bacteria. Bacterial lipopolysaccharide (LPS) induces an inflammatory response in RAW 264.7 macrophages. PN5 suppressed proinflammatory cytokines mediated by NF-κB and mitogen-activated protein kinase signaling. In C57BL/6J mice treated with LPS and d-galactosamine, PN5 exhibited anti-inflammatory activity in inflamed mouse livers. Our results indicate that PN5 has antimicrobial and anti-inflammatory activities and thus may be useful as an antimicrobial agent to treat septic shock caused by multidrug-resistant (MDR) Escherichia coli without causing further resistance. IMPORTANCE Antibiotic-resistant bacteria are a global health concern. There is no effective treatment for antibiotic-resistant bacteria, and new alternatives are being suggested. The present study found antibacterial and anti-inflammatory activities of PN5 derived from Pinus densiflora (pine needle), and further investigated the therapeutic effect in a mouse septic model. As a mechanism of antibacterial activity, PN5 exhibited the membrane permeabilization ability of the toroidal model, and treated strains did not develop drug resistance during serial passages. PN5 showed immunomodulatory properties of neutralizing LPS in a mouse septic model. These results indicate that PN5 could be a new and promising therapeutic agent for bacterial infectious disease caused by antibiotic-resistant strains.

Antimicrobial resistance, virulence factors, and genotypes of Pseudomonas aeruginosa clinical isolates from Gorgan, northern Iran.

Pseudomonas aeruginosa is an important nosocomial pathogen with a capacity of resistance to multiple antibiotics and production of various extracellular and cell-associated virulence factors that clearly contribute to its pathogenicity. The objective of this study was to investigate the antibiotic susceptibility, virulence factors, and clonal relationship among clinical isolates of P. aeruginosa. Different clinical specimens from hospitalized patients were investigated for P. aeruginosa. Susceptibility of the isolates was evaluated by disc diffusion and broth microdilution methods, as described by the Clinical and Laboratory Standards Institute (CLSI) guideline. A total of 97 P. aeruginosa isolates were recovered from clinical specimens. The percentage of isolates resistant to antimicrobials was imipenem 25.77%, meropenem 15.46%, gentamicin 16.49%, tobramycin 15.46%, amikacin 16.49%, ciprofloxacin 20.61%, levofloxacin 24.74, ceftazidime 20.61%, piperacillin 15.46%, piperacillin/tazobactam 12.37%, colistin 9.27%, and polymyxin B 11.34%. Of isolates, 87.62% possessed ß-hemolytic activity, 78.35% lecithinase, 59.8% elastase, 37.11% DNase, and 28.86% twitching motility. The frequency of virulence genes in isolates was lasB 82.47%, plcH 82.47%, exoA 58.76%, exoS 56.7%, and pilA 10.3%. ERIC-PCR typing clustered P. aeruginosa isolates to 19 common types (CT1-CT19) containing isolates from different hospitals and 43 single types (ST1-ST43). Colistin and polymyxin B were the most effective agents against the majority of P. aeruginosa isolates, emphasizing the effort to maintain their antibacterial activity as last-line therapy. The frequency of some virulence factors and genes was noticeably high, which is alarming. In addition, more effective strategies and surveillance are necessary to confine and prevent the inter-hospital and/or intra-hospital dissemination of P. aeruginosa between therapeutic centers.

Budesonide/glycopyrronium/formoterol fumarate triple therapy prevents pulmonary hypertension in a COPD mouse model via NFκB inactivation.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a health problem that results in death, commonly due to the development of pulmonary hypertension (PH). Here, by utilizing a mouse model of intratracheal elastase-induced emphysema that presents three different phases of COPD, we sought to observe whether budesonide/glycopyrronium/formoterol fumarate (BGF) triple therapy could prevent COPD-PH in addition to ameliorating COPD progression. METHODS: We utilized intratracheal elastase-induced emphysema mouse model and performed experiments in three phases illustrating COPD progression: inflammatory (1 day post-elastase), emphysema (3 weeks post-elastase) and PH (4 weeks post-elastase), while treatments of BGF and controls (vehicle, one-drug, and two-drug combinations) were started in prior to elastase instillation (inflammatory phase), at day 7 (emphysema), or at day 14 (PH phase). Phenotype analyses were performed in each phase. In vitro, A549 cells or isolated mouse lung endothelial cells (MLEC) were treated with TNFα with/without BGF treatment to analyze NFκB signaling and cytokine expression changes. RESULTS: We observed significant reductions in the proinflammatory phenotype observed in the lungs and bronchoalveolar lavage fluid (BALF) 1 day after elastase administration in mice treated with BGF compared with that in mice administered elastase alone (BALF neutrophil percentage, p = 0.0011 for PBS/Vehicle vs. PBS/Elastase, p = 0.0161 for PBS/Elastase vs. BGF). In contrast, only BGF treatment significantly ameliorated the elastase-induced emphysematous lung structure and desaturation after three weeks of elastase instillation (mean linear intercept, p = 0.0156 for PBS/Vehicle vs. PBS/Elastase, p = 0.0274 for PBS/Elastase vs. BGF). Furthermore, BGF treatment prevented COPD-PH development, as shown by improvements in the hemodynamic and histological phenotypes four weeks after elastase treatment (right ventricular systolic pressure, p = 0.0062 for PBS/Vehicle vs. PBS/Elastase, p = 0.027 for PBS/Elastase vs. BGF). Molecularly, BGF acts by inhibiting NFκB-p65 phosphorylation and subsequently decreasing the mRNA expression of proinflammatory cytokines in both alveolar epithelial and pulmonary endothelial cells. CONCLUSION: Our results collectively showed that BGF treatment could prevent PH in addition to ameliorating COPD progression via the inhibition of inflammatory NFκB signaling.

The investigation and management of pancreatic exocrine insufficiency: A retrospective cohort study.

Pancreatic exocrine insufficiency (PEI) is associated with significant gastrointestinal symptoms, but is readily treated by pancreatic enzyme replacement therapy (PERT). We reviewed our current practice and examined the factors that predict repeating a positive faecal elastase-1 (FE1; <200 µg/g), the repeat FE1 being normal, initiation of PERT and clinical response to treatment. A single-centre retrospective cohort study was conducted. Outpatients with FE1 <200 µg/g between 2012 and 2018 were included. Logistic regression was used to explore the associations with each outcome, with statistical adjustment for confounders. Two-hundred and ten patients were included; 28.1% of patients had their FE1 repeated, 47.5% of whom had a normal repeat result. Patients with initial FE1 <15 µg/g were unlikely to be reclassified on repeat testing. Patients with a confirmatory low FE1, abnormal pancreatic imaging or abnormal nutrition blood tests were more likely to be started on PERT (all p<0.05). Patients with abnormal pancreatic imaging were 10 times more likely to respond to PERT (odds ratio 10.70; 95% confidence interval 1.62-70.70; p=0.01). Augmenting clinical judgement with pancreatic imaging and repeat FE1 testing could improve the rate of PERT prescription and inform the approach to non-response, particularly in cases where there is diagnostic doubt.

Primary Cilia Deficiency Induces Intracranial Aneurysm.

BACKGROUND: Intracranial aneurysm (IA) rupture is life-threatening. However, the mechanisms underlying IA initiation, progression, and rupture remain poorly understood. In the present study, we examined the role of primary cilia in IA development. RESULTS: IA was experimentally induced in mice with elastase and angiotensin II treatment. The number of cells with primary cilia was determined in both IA and peri-IA regions. The role of primary cilia in IA development was assessed through knocking out or manipulating the expression of important components of primary cilia. Finally the role of primary cilia in human IA patients was studied. In the mice model of IA, the primary cilia number was significantly decreased in the IA region. Knocking out Polycystin 1, Polycystin 2, and Intraflagellar Transport 88 in mice would increase the susceptibility of mice to IA development. The IA development could be modulated through manipulating the pathways that regulate primary cilia dynamics. And chemical screening showed that the three factors (PHA 680623, Rapamycin, and Forskolin) could efficiently suppress the IA development. Finally, we demonstrated that the primary cilia deficiency in IA development is conserved in humans. And IA patients had a higher frequency of gene mutations which are related to primary cilia regulation. CONCLUSION: Our study provides an important support for the role of primary cilia in the development of IA. The primary cilia stabilizing chemicals might be useful for preventing IA development.

Pulmonary Emphysema Cross-Linking with Pulmonary Fibrosis and Vice Versa: a Non-usual Experimental Intervention with Elastase and Bleomycin.

Elastase (PPE) is usually used for emphysema models, whereas bleomycin (BLM) is used for fibrosis models. The aim of this study was to investigate the effect of BLM in PPE-induced emphysema, as well as the effect of PPE in BLM-induced fibrosis. C57BL/6 mice were divided into five groups: control, PPE, BLM, PPE + BLM, and BLM + PPE. Mice received saline, PPE (3 U/mouse), or BLM (20 U/kg) by intranasal instillation. Mice from the BLM and BLM + PPE groups received BLM on day 0 and saline or PPE on day 21, respectively. Those in the PPE and PPE + BLM groups received PPE on day 0 and saline or BLM on day 21, respectively. Mice were euthanized on day 42. We performed histology, morphometry in lung sections and ELISA, zymography and western blotting in BAL samples or lung homogenates. In the lungs of PPE + BLM and BLM + PPE groups, we observed inflammation, oxidative stress and expression of MMP-2 and MMP-9. The alveolar enlargement was reduced in the PPE + BLM group, suggesting that the BLM could participate in the alveolar remodeling process. The significance of this result supports future therapeutic approaches targeting extracellular-matrix deposition in patients with emphysema as a way to repair the enlargement of alveoli and airspaces.

Arteriovenous fistula patency in the 3 years following vonapanitase and placebo treatment.

OBJECTIVE: This study explored the long-term outcomes of arteriovenous fistulas treated with vonapanitase (recombinant human elastase) at the time of surgical creation. METHODS: This was a randomized, double-blind, placebo-controlled trial of 151 patients undergoing radiocephalic or brachiocephalic arteriovenous fistula creation who were randomized equally to placebo, vonapanitase 10 µg, or vonapanitase 30 µg. The results after 1 year of follow-up were previously reported. The current analysis occurred when the last patient treated was observed for 3 years. For the current analysis, the primary end point was primary patency; the secondary end points included secondary patency, use of the fistula for hemodialysis, and rate of procedures to restore or to maintain patency. RESULTS: There was no significant difference in the risk of primary patency loss with vonapanitase 10 µg or 30 µg vs placebo. When seven initial patency loss events related to cephalic arch and central vein balloon angioplasty were excluded, the risk of patency loss was reduced with vonapanitase overall (hazard ratio [HR], 0.63; P = .049) and 30 µg (HR, 0.51; P = .03). In patients with radiocephalic fistulas (n = 67), the risks of primary and secondary patency loss were reduced with 30 µg (HR, 0.37 [P = .02] and 0.24 [P = .046], respectively). The rate of procedures to restore or to maintain fistula patency was reduced with 30 µg vs placebo (0.23 vs 0.72 procedure days/patient/year; P = .03) and also reduced in patients with radiocephalic fistulas with 30 µg vs placebo (0.17 vs 0.85 procedure days/patient/year; P = .048). CONCLUSIONS: In this study, vonapanitase did not significantly improve primary patency in the primary analysis but did significantly improve primary patency in an analysis that excluded patency loss due to cephalic arch and central vein balloon angioplasty. In patients with radiocephalic fistulas, 30 µg significantly improved primary and secondary patency. Vonapanitase 30 µg decreased the rate of procedures to restore or to maintain patency in the analysis that included all patients and in the subset with radiocephalic fistulas.

Lung structure and function in elastase-treated rats: A follow-up study.

Structural and functional longitudinal alterations of the lungs were followed in an emphysema model. Rats were treated with porcine pancreatic elastase (PPE, n=21) or saline (controls, C, n=19). Before the treatment and 3, 10, 21 and 105 days thereafter, absolute lung volumes (FRC, TLC and RV) and tissue mechanical parameters (elastance: H; damping: G) were determined. At 3, 21 and 105 days the lungs were fixed in subgroups of rats. From histological samples the equivalent diameter of airspaces (Dalv), elastin (Mec) and collagen densities were assessed. In the PPE group, FRC and RV were higher from 3 days after treatment compared to controls (p<0.001), while TLC exhibited a delayed increase. H and G decreased in the PPE group throughout the study (p<0.001). Higher Mec (p<0.001) and late-phase inflammation were observed at 105 days. We conclude that during the progression of emphysema, septal failures increase Dalv which decreases H; this reveals a strong structure-function relationship.

Establishment of a new murine elastase-induced aneurysm model combined with transplantation.

INTRODUCTION: The aim of our study was to develop a reproducible murine model of elastase-induced aneurysm formation combined with aortic transplantation. METHODS: Adult male mice (n = 6-9 per group) underwent infrarenal, orthotopic transplantation of the aorta treated with elastase or left untreated. Subsequently, both groups of mice were monitored by ultrasound until 7 weeks after grafting. RESULTS: Mice receiving an elastase-pretreated aorta developed aneurysms and exhibited a significantly increased diastolic vessel diameter compared to control grafted mice at 7 week after surgery (1.11 ± 0.10 mm vs. 0.75 ± 0.03 mm; p ≤ 0,001). Histopathological examination revealed disruption of medial elastin, an increase in collagen content and smooth muscle cells, and neointima formation in aneurysm grafts. CONCLUSIONS: We developed a reproducible murine model of elastase-induced aneurysm combined with aortic transplantation. This model may be suitable to investigate aneurysm-specific inflammatory processes and for use in gene-targeted animals.

In vivo feasibility case study for evaluating abdominal aortic aneurysm tissue properties and rupture potential using acoustic radiation force impulse imaging.

An abdominal aortic aneurysm (AAA) is defined as a permanent and irreversible localized dilatation of the abdominal aorta. A reliable, non-invasive method to assess the wall mechanics of an aneurysm may provide additional information regarding their susceptibility to rupture. Acoustic radiation force impulse (ARFI) imaging is a phenomenon associated with the propagation of acoustic waves in attenuating media. This study was a preliminary evaluation to explore the feasibility of using ARFI imaging to examine an AAA in vivo. A previously diagnosed in vivo aneurysm case study was imaged to demonstrate the viability of excitation of the abdominal aorta using ARFI imaging. Ex vivo experiments were used to assess an artificially induced aneurysm to establish its development and whether ARFI was able to capture the mechanical changes during artificial aneurysm formation. A combination of in vivo and ex vivo results demonstrated a proposed hypothesis of estimation of the tissue's stiffness properties. The study details a method for non-invasive rupture potential prediction of AAAs using patient-specific moduli to generate a physiological stiffness rupture potential index (PSRPI) of the AAA. Clinical feasibility of ARFI imaging as an additional surgical tool to interrogate AAAs was verified and methods to utilize this data as a diagnostic tool was demonstrated with the PSRPI.

Reduced expression of virulence factors in multidrug-resistant Pseudomonas aeruginosa strains.

MDR Pseudomonas aeruginosa strains are isolated from clinical specimens with increasing frequency. It seems that acquiring genes which determine antibiotic resistance usually comes at a biological cost of impaired bacterial physiology. There is no information on investigations comparing phenotypic differences in MDR and MDS P. aeruginosa strains in literature. The study included 150 clinical P. aeruginosa isolates (75 classified as MDS and 75 as MDR). PFGE analysis revealed five pairs of identical isolates in the group of MDR strains and the results obtained for these strains were not included in the statistical analyses. MDR strains adhered to polystyrene to a lesser extent than MDS strains. The growth rate in the liquid medium was significantly lower for MDR strains. Detectable amounts of alginate were present in the culture supernatants of seven MDS and six MDR strains. The MDR P. aeruginosa strains which were investigated produced significantly lower amounts of extracellular material binding Congo Red, lower lipolytic, elastase, LasA protease, phospholipase C activity and pyocyanin quantity in culture supernatants when compared with MDS strains. No significant differences were observed between MDR and MDS strains in proteolytic activity. In conclusion, the MDR P. aeruginosa strains have impaired virulence when compared to MDS strains.

Animal models of arterial stiffness.

Animal models of large artery wall stiffness fall into two categories: firstly those that slowly develop multifactorial vascular dysfunction spontaneously, such as the ageing rat. The second type of model consists of those in which a specific pathology is induced by surgical, chemical, or genetic means. Such models are based on a short-term, highly traumatic insult to the arterial wall of a young animal and its acute reaction to such insult. This is very different from the human situation in which changes in wall stiffness arise from the long-term accumulation of relatively minor episodes of vascular insult in the vulnerable elderly.

Alterations in angiotensin converting enzyme during rodent aortic aneurysm formation.

BACKGROUND: The renin-angiotensin system (RAS) has been implicated in vessel wall remodeling. This investigation tested the hypothesis that the RAS is altered during experimental rodent aneurysm formation. MATERIALS AND METHODS: Rat aortas were perfused with saline (controls, N = 45) or elastase (6 U/ml, N = 45). At 4, 7, and 14 days after aortic perfusion, aortic diameters were measured (n = 15/time point/group) and aortic wall mRNA and protein were extracted. Real time polymerase chain reation (PCR) measured RNA levels of angiotensin, angiotensin converting enzyme (ACE), angiotensin II receptor 1 (AT(1)), and angiotensin II receptor 2 (AT(2)). Western blot analysis measured ACE protein levels. Immunohistochemical studies localized ACE within the aortic wall. Statistical analyses were performed with the unpaired t-test and ANOVA. RESULTS: Elastase perfusion significantly increased aortic diameter (P < 0.01), with no significant changes in saline control aortic diameters. ACE mRNA did not become elevated in elastase-perfused aortas, yet ACE protein levels were elevated on days 4 and 7 of perfusion (P < 0.01) compared to controls, and ACE staining was noted in these aortas. This difference resolved by 14 days. In neither group were there significant alterations in AT(1), AT(2), or An mRNA levels, although ACE mRNA was elevated in controls after 7 days of perfusion compared to elastase perfused aortas (P < 0.005). CONCLUSIONS: Experimental aortic aneurysm formation may be associated with increased aortic wall ACE protein levels. The mechanisms by which these proteins contribute to, or serve as markers of, aneurysm formation in vivo requires further intervention.

Pancreatic enzyme therapy and clinical outcomes in patients with cystic fibrosis.

OBJECTIVE: To assess the relationship between pancreatic enzyme therapy (PET) and the clinical outcomes of growth, abdominal pain, constipation, gassiness, and number of stools in cystic fibrosis (CF). STUDY DESIGN: Patients (n = 1215) >4 weeks of age from 33 Cystic Fibrosis Foundation accredited sites who had a sweat chloride >60 mmol/L or two CF-causing mutations were enrolled using a proportionate sampling strategy in a nonblinded study. Patients submitted a stool sample and completed a questionnaire. The study coordinator also completed a questionnaire for each patient. Enzyme dosing and growth, abdominal pain, gassiness, constipation, and number of stools were compared. RESULTS: Of the 1215 enrolled patients, 1131 (93.1%) were prescribed PET. Only 14.9% had pancreatic function assessed before enrolling in this study. Stool elastase-1 analysis identified 1074 (89%) patients as pancreatic insufficient (PI). There was no association between PET and the outcomes: growth, abdominal pain, gassiness, constipation, and number of stools. CONCLUSION: PET dose is not correlated with growth or gastrointestinal symptoms. More sensitive outcome measures of the effectiveness of PET in patients with CF are needed to guide treatment of PI.