Advanced Abdominal Aortic Aneurysm Modeling in Mice by Combination of Topical Elastase and Oral ß-aminopropionitrile.

The topical elastase murine model of abdominal aortic aneurysm (AAA) is enhanced when combined with ß-aminopropionitrile (BAPN)-supplemented drinking water to reliably produce true infrarenal aneurysms with behaviors that mimic human AAAs. Topically applying elastase to the adventitia of the infrarenal aorta causes structural damage to the elastic layers of the aortic wall and initiates aneurysmal dilation. Co-administering BAPN, a lysyl oxidase inhibitor, promotes sustained wall degeneration by reducing collagen and elastin crosslinking. This combination results in large AAAs that progressively expand, form intraluminal thrombus, and are capable of rupture. Refining surgical techniques, such as circumferentially isolating the entire infrarenal aortic segment, can help standardize the procedure for a consistent and thorough application of porcine pancreatic elastase despite different operators and anatomic variations between mice. Therefore, the elastase/BAPN model is a refined approach to surgically inducing AAA in mice, which may better recapitulate human aneurysms and provide additional opportunities to study aneurysm growth and rupture risk.

Radiofrequency therapy improves exercise capacity of mice with emphysema.

Emphysema is a common phenotype of chronic obstructive pulmonary disease (COPD). Although resection of emphysematous tissue can improve lung mechanics, it is invasive and fraught with adverse effects. Meanwhile, radiofrequency (RF) treatment is an extracorporeal method that leads to tissue destruction and remodeling, resulting in "volume reduction" and overall improvement in lung compliance of emphysematous lungs. Whether these changes lead to improved exercise tolerance is unknown. Here, we investigated the effectiveness of RF treatment to improve the exercise capacity of mice with emphysema. Fifty-two mice (7 weeks of age) were used in this experiment. A bilateral emphysema model was created by intratracheally instilling porcine pancreatic elastase (PPE) (1.5U/100 g body weight). RF treatment (0.5 W/ g body weight) was administered extracorporeally 14 days later and mice were sacrificed after another 21 days. The exercise capacity of mice was measured using a treadmill. Treadmill runs were performed just before PPE instillation (baseline), before RF treatment and before sacrifice. Following sacrifice, lung compliance and mean linear intercept (Lm) were measured and fibrosis was assessed using a modified Ashcroft score. There were 3 experimental groups: controls (instilled with saline, n = 12), emphysema (instilled with porcine pancreatic elastase, PPE, n = 11) and emphysema + treatment (instilled with PPE and given RF, n = 9). At endpoint, the maximum velocity of the emphysema + treatment group was significantly higher than that of the emphysema group, indicating improved exercise tolerance (86.29% of baseline vs 61.69% of baseline, p = 0.01). Histological analysis revealed a significant reduction in emphysema as denoted by Lm between the two groups (median 29.60 µm vs 35.68 µm, p = 0.03). The emphysema + treatment group also demonstrated a higher prevalence of lung fibrosis (≧Grade 3) compared with the emphysema group (11.7% vs 5.4%, p < 0.01). No severe adverse events from RF were observed. RF treatment improved the exercise capacity of mice with emphysema. These data highlight the therapeutic potential of RF treatment in improving the functional status of patients with COPD.

Betanin Prevents Experimental Abdominal Aortic Aneurysm Progression by Modulating the TLR4/NF-κB and Nrf2/HO-1 Pathways.

Betanin, a bioactive ingredient mostly isolated from beetroots, exhibits a protective effect against cardiovascular diseases. However, its effects on abdominal aortic aneurysm (AAA) have not been elucidated. In this study, an AAA model was constructed by infusion of porcine pancreatic elastase in C57BL/6 mice. Mice were then administered with betanin or saline intragastrically once daily for 14 d. Our results showed that treatment with betanin remarkably limited AAA enlargement and mitigated the infiltration of inflammatory cells in the adventitia. The increased expression of proinflammatory cytokines and matrix metalloproteinases (MMPs) was also significantly alleviated following betanin treatment. Furthermore, betanin suppressed the activation of toll-like receptor 4 (TLR4)/nuclear factor-kappaB (NF-κB) signaling in the aortic wall, and downregulated the levels of tissue-reactive oxygen species as well as circulating 8-isoprostane by stimulating the nuclear factor-E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. Taken together, these data suggest that betanin may attenuate AAA progression and may be used as a therapeutic drug against AAA.

Therapeutic benefits of recombinant alpha1-antitrypsin IgG1 Fc-fusion protein in experimental emphysema.

BACKGROUND: Alpha-1 antitrypsin (AAT) is a major serine protease inhibitor. AAT deficiency (AATD) is a genetic disorder characterized by early-onset severe emphysema. In well-selected AATD patients, therapy with plasma-derived AAT (pAAT), "augmentation therapy", provides modest clinical improvement but is perceived as cumbersome with weekly intravenous infusions. Using mouse models of emphysema, we compared the effects of a recombinant AAT-IgG1 Fc-fusion protein (AAT-Fc), which is expected to have a longer half-life following infusion, to those of pAAT. METHODS: In an elastase model of emphysema, mice received a single intratracheal instillation of porcine pancreatic elastase (PPE) or human leucocyte elastase (hLE). AAT-Fc, pAAT, or vehicle was administered intraperitoneally 1 day prior to or 3 weeks following elastase instillation. Lung function and histology assessments were performed at 7 and 32 days after elastase instillation. In a cigarette smoke (CS) model of emphysema, mice were exposed to CS daily, 5 days a week, for 6 months and AAT-Fc, pAAT, or vehicle were administered every 10 days during the last 3 months of CS exposure. Assessments were performed 3 days after the last CS exposure. Immune responses to lung elastin peptide (EP) and the effects of AAT-Fc or pAAT treatment on dendritic cell (DC) function were determined ex vivo. RESULTS: Both elastase instillation and CS exposure triggered emphysema-like alveolar enlargement, increased lung compliance, and increased markers of inflammation compared to controls. Administration of AAT-Fc either prior to or following elastase instillation or during CS exposure provided greater protection than pAAT against alveolar enlargement, lung dysfunction, and airway inflammation. When challenged ex vivo with EP, spleen mononuclear cells from elastase-exposed mice exhibited dose-dependent production of IFNγ and IL-17, suggesting immune reactivity. In co-culture experiments with splenic CD4+ T cells isolated from elastase-exposed mice, AAT-Fc treatment prior to EP-priming of bone marrow-derived dendritic cells inhibited the production of IFNγ and IL-17. CONCLUSIONS: Compared to pAAT, AAT-Fc more effectively prevented or attenuated elastase- and CS-induced models of emphysema. These effects were associated with immunomodulatory effects on DC activity. AAT-Fc may provide a therapeutic option to individuals with AATD- and CS-induced emphysema.

Testosterone deficiency promotes the development of pulmonary emphysema in orchiectomized mice exposed to elastase.

Testosterone deficiency is commonly observed in male patients with chronic obstructive pulmonary disease (COPD), which is characterized by chronic inflammation of the airways and pulmonary emphysema. Although clinical trials have indicated that testosterone replacement therapy can improve respiratory function in patients with COPD, the role of testosterone in the pathogenesis of COPD remains unclear. The aim of this study was to explore the effect of testosterone deficiency on the development of pulmonary emphysema in orchiectomized (ORX) mice exposed to porcine pancreatic elastase (PPE). ORX mice developed more severe emphysematous changes 21 d after PPE inhalation than non-ORX mice. Testosterone propionate supplementation significantly reduced PPE-induced emphysematous changes in ORX mice. PPE exposure also increased the number of neutrophils and T cells in bronchoalveolar lavage fluid (BALF) of mice that had undergone ORX and sham surgery. T cell counts were significantly higher in the BALF of ORX mice than of sham mice. Testosterone supplementation reduced the infiltration of T cells into BALF and alleviated emphysematous changes in the lungs of ORX mice. Our findings suggest that testosterone, a male-specific hormone, may suppress the development of pulmonary emphysema through the regulation of T cell-mediated immunity.

Rabbit Elastase Aneurysm: Imaging and Histology Correlates for Inflammation and Healing.

OBJECTIVE: Aneurysmal subarachnoid hemorrhage remains a devastating event with poorly understood pathophysiology. Previous studies have suggested that aneurysm wall inflammation may play a part in the development and potential rupture of aneurysms. The rabbit elastase aneurysm model is a well-established model, which produces aneurysms closely mimicking human cerebral aneurysms in flow dynamics and histopathology. The primary aim of this study was to correlate inflammatory changes after aneurysm formation using sequential vessel wall imaging with histopathologic analysis. A secondary aim was to evaluate the potential effect of gender and anti-inflammatory treatment with aspirin on this inflammatory response. METHODS: Twenty-seven New Zealand rabbits underwent surgery to create an aneurysm using elastase infusion at the right common carotid artery origin. Vessel wall imaging and histopathologic analysis was obtained at different time points after aneurysm creation. The rabbits were also randomized by gender and to treatment groups with or without aspirin. RESULTS: Histopathologic analysis revealed 3 distinct phases after aneurysm formation. These phases were an initial inflammatory phase, followed by a regeneration phase, and finally a connective tissue deposition phase. Vessel wall imaging demonstrated 2 distinct imaging patterns. No appreciable differences were seen in histology or imaging when comparing gender or treatment with aspirin. CONCLUSIONS: Inflammatory changes induced by the rabbit elastase aneurysm model can be correlated with histopathologic findings and observed on noninvasive vessel wall imaging. This may provide a method to study the inflammatory pathway as it pertains to aneurysmal development and subsequent rupture.

Immune responses in mice vaccinated with a DNA vaccine expressing a new elastase from Trichinella spiralis.

The elastase, which belongs to the serine protease family, hydrolyses various proteins and may be involved in the parasite invasion. In this study, complete sequence of elastase-1 (TsE) the nematode Trichinella spiralis (Owen, 1835) was cloned into the plasmid pcDNA3.1 as TsE DNA vaccine. After intramuscular vaccination, serum anti-Trichinella antibodies (IgG and subclass IgG1/IgG2a, and IgA), total and specific intestinal mucosal sIgA in mice vaccinated with pcDNA3.1/TsE were measured by ELISA. The results showed that vaccination with pcDNA3.1/TsE induced a systemic humoral immune response (high levels of serum IgG and subclass IgG1/IgG2a and IgA) and local intestinal mucosal immune responses (high levels of TsE-specific sIgA). Vaccination of mice with TsE DNA vaccine also triggered a systemic and local concomitant Th1/Th2 response, as demonstrated by significant elevation of Th1 (IFN-γ and IL-2) / Th2 (IL-4 and IL-10) cytokine levels after the spleen, mesenteric lymph node and Peyer's patch cells from vaccinated mice were stimulated with recombinant TsE (rTsE). The vaccination of mice with pcDNA3.1/TsE displayed a 17% reduction of intestinal adult worms and a 39% reduction of muscle larvae. Our results indicated that TsE DNA vaccine elicited a systemic concomitant Th1/Th2 response and an enteral local sIgA response, and produced a partial protection against infection with T. spiralis. The TsE may be regarded as a potential candidate vaccine target against Trichinella infection. The oral polyvalent vaccines should be developed to improve the protective efficacy of anti-Trichinella vaccines.

Intraluminal infusion of Penta-Galloyl Glucose reduces abdominal aortic aneurysm development in the elastase rat model.

BACKGROUND: An abdominal aortic aneurysm (AAA) is a progressive chronic dilatation of the abdominal aorta with terminally rupture when the aortic wall is so weakened that aortic wall stress exceeds wall strength. No effective medical treatment exists so far. We aimed to test whether intraluminal admission of Penta-Galloyl Glucose (PGG) treatment in a rodent AAA model could hold the potential to inhibit aneurysmal progression. METHOD: Male Sprague Dawley rats had either intraluminal elastase infused for AAA induction or saline to serve as controls. In two independent experimental series, elastase was used to induce AAA followed by an intraluminal PGG (directly or by a drug eluting balloon) treatment. All rats were followed for 28 days and euthanized. In both series, maximal infrarenal aortic diameter was measured at baseline and at termination as a measure of AAA size. In series 2, maximal internally AAA diameter was followed by ultrasound weekly. AAA tissues were analyzed for elastin integrity by millers stain, collagen deposition by masson trichrome staining. In other AAA tissue samples the mRNA level of CD45, lysyloxidase (LOX), lysyloxidase like protein 1 (LOXL1) were determined by qPCR. RESULTS: Direct administration of PGG significantly reduced AAA expansion when compared to controls. PGG treatment resulted in a higher number and more preserved elastic fibers in the aneurysmal wall, while no significant difference was seen in the levels of CD45 and LOX mRNA levels. The drug eluting balloon (DEB) experiment showed no significant difference in AAA size observed neither macroscopically nor ultrasonically. Also the aneurysmal mRNA levels of CD45, LOX and LOXL1 were unchanged between groups. CONCLUSION: A significant reduced expansion of AAAs was observed in the PGG group, suggesting PGG as a drug to inhibit aneurysmal progression, while administration through a DEB did not show a promising new way of administration.

Blockade of Dopamine D2 Receptors as a Novel Approach to Stimulation of Notch1+ Endothelial Progenitor Cells and Angiogenesis in C57BL/6 Mice with Pulmonary Emphysema Induced by Proteases and Deficiency of α1-Antitrypsin.

We studied the effects of spiperone, a selective blocker of dopamine D2 receptors, on the model of pulmonary emphysema provoked by administration of elastase and D-galactosamine hydrochloride to female C57BL/6 mice and characterized by activation of proteases in the lungs and systemic deficiency of its inhibitor α1-antitrypsin. In this model, spiperone prevented the development of inflammatory reaction and reduced the area of emphysematous expanded alveolar tissue. The expression of angiogenic marker CD31 in the lungs increased under these conditions. Regeneration of the damaged microvascular bed under the action of spiperone resulted from recruiting of Notch1+ endothelial progenitor cells (CD45-CD31+CD34+) into the lungs and blockade of the inhibitory effect of dopamine on phosphorylation of VEGF-2 receptors in endothelial cells of different maturity. In addition, spiperone produced a protective effect on hepatocytes and restored the production and secretion of α1-antitrypsin by these cells.

Protective immunity in mice vaccinated with a novel elastase-1 significantly decreases Trichinella spiralis fecundity and infection.

Trichinella spiralis is an important foodborne parasitic nematode that represents an enormous threat to the food safety of pork meat. The development of a preventive vaccine is valuable for the prevention and control of Trichinella infection in domestic pigs to ensure pork safety. Elastase is a trypsin-like serine protease that hydrolyzes the host's diverse tissue components and participates in parasite penetration, and it might be a novel vaccine target molecule. The aim of this study was to assess the protective immunity produced by vaccination with a novel Trichinella spiralis elastase-1 (TsE) in a mouse model. The results demonstrate that subcutaneous vaccination of mice with rTsE elicited a systemic humoral response (high levels of serum IgG and subclass IgG1/IgG2a and IgA) and significant local enteral mucosal sIgA responses. Anti-rTsE IgG recognized the native TsE at the cuticle, stichosome of intestinal infective larvae and adult worm (AW), and intrauterine embryos of female AW. The rTsE vaccination also produced a systemic and local mixed Th1/Th2 response, as demonstrated by clear elevation levels of Th1 cytokines (IFN-γ, IL-2) and Th2 cytokines (IL-4, IL-10) after spleen, mesenteric lymph node and Peyer's patch cells from immunized mice were stimulated with rTsE. The immunized mice exhibited a 52.19% reduction in enteral AW and a 64.06% reduction in muscle larvae after challenge infection. The immune response triggered by rTsE vaccination protected enteral mucosa from larval intrusion, suppressed larval development and reduced female fecundity. The results indicate that TsE may represent a novel target molecule for anti-T. spiralis vaccines.

Nanoparticle-based targeted delivery of pentagalloyl glucose reverses elastase-induced abdominal aortic aneurysm and restores aorta to the healthy state in mice.

AIM: Abdominal aortic aneurysms (AAA) is a life-threatening weakening and expansion of the abdominal aorta due to inflammatory cell infiltration and gradual degeneration of extracellular matrix (ECM). There are no pharmacological therapies to treat AAA. We tested the hypothesis that nanoparticle (NP) therapy that targets degraded elastin and delivers anti-inflammatory, anti-oxidative, and ECM stabilizing agent, pentagalloyl glucose (PGG) will reverse advance stage aneurysm in an elastase-induced mouse model of AAA. METHOD AND RESULTS: Porcine pancreatic elastase (PPE) was applied periadventitially to the infrarenal aorta in mice and AAA was allowed to develop for 14 days. Nanoparticles loaded with PGG (EL-PGG-NPs) were then delivered via IV route at 14-day and 21-day (10 mg/kg of body weight). A control group of mice received no therapy. The targeting of NPs to the AAA site was confirmed with fluorescent dye marked NPs and gold NPs. Animals were sacrificed at 28-d. We found that targeted PGG therapy reversed the AAA by decreasing matrix metalloproteinases MMP-9 and MMP-2, and the infiltration of macrophages in the medial layer. The increase in diameter of the aorta was reversed to healthy controls. Moreover, PGG treatment restored degraded elastic lamina and increased the circumferential strain of aneurysmal aorta to the healthy levels. CONCLUSION: Our results support that site-specific delivery of PGG with targeted nanoparticles can be used to treat already developed AAA. Such therapy can reverse inflammatory markers and restore arterial homeostasis.

Chronic exposure to diesel particles worsened emphysema and increased M2-like phenotype macrophages in a PPE-induced model.

Chronic exposure to ambient levels of air pollution induces respiratory illness exacerbation by increasing inflammatory responses and apoptotic cells in pulmonary tissues. The ineffective phagocytosis of these apoptotic cells (efferocytosis) by macrophages has been considered an important factor in these pathological mechanisms. Depending on microenvironmental stimuli, macrophages can assume different phenotypes with different functional actions. M1 macrophages are recognized by their proinflammatory activity, whereas M2 macrophages play pivotal roles in responding to microorganisms and in efferocytosis to avoid the progression of inflammatory conditions. To verify how exposure to air pollutants interferes with macrophage polarization in emphysema development, we evaluated the different macrophage phenotypes in a PPE- induced model with the exposure to diesel exhaust particles. C57BL/6 mice received intranasal instillation of porcine pancreatic elastase (PPE) to induce emphysema, and the control groups received saline. Both groups were exposed to diesel exhaust particles or filtered air for 60 days according to the groups. We observed that both the diesel and PPE groups had an increase in alveolar enlargement, collagen and elastic fibers in the parenchyma and the number of macrophages, lymphocytes and epithelial cells in BAL, and these responses were exacerbated in animals that received PPE instillation prior to exposure to diesel exhaust particles. The same response pattern was found inCaspase-3 positive cell analysis, attesting to an increase in cell apoptosis, which is in agreement with the increase in M2 phenotype markers, measured by RT-PCR and flow cytometry analysis. We did not verify differences among the groups for the M1 phenotype. In conclusion, our results showed that both chronic exposure to diesel exhaust particles and PPE instillation induced inflammatory conditions, cell apoptosis and emphysema development, as well as an increase in M2 phenotype macrophages, and the combination of these two factors exacerbated these responses. The predominance of the M2-like phenotype likely occurred due to the increased demand for efferocytosis. However, M2 macrophage activity was ineffective, resulting in emphysema development and worsening of symptoms.

A randomized trial of vonapanitase (PATENCY-1) to promote radiocephalic fistula patency and use for hemodialysis.

OBJECTIVE: Arteriovenous fistulas created in patients with chronic kidney disease often lose patency and fail to become usable. This prospective trial evaluated the efficacy of vonapanitase, a recombinant human elastase, in promoting radiocephalic fistula patency and use for hemodialysis. METHODS: PATENCY-1 was a double-blind, placebo-controlled trial that enrolled 349 patients on or approaching hemodialysis and being evaluated for radiocephalic arteriovenous fistula creation. Of these, 313 were randomized and 311 treated. Patients were assigned to vonapanitase (n = 210) or placebo (n = 103). The study drug solution was applied topically to the artery and vein for 10 minutes immediately after fistula creation. The primary and secondary end points were primary patency (time to first thrombosis or corrective procedure) and secondary patency (time to abandonment). Tertiary end points included use of the fistula for hemodialysis, fistula maturation by ultrasound, and procedure rates. RESULTS: The Kaplan-Meier estimates of 12-month primary patency were 42% (95% confidence interval [CI], 35-49) and 31% (95% CI, 21-42) for vonapanitase and placebo (P = .25). The Kaplan-Meier estimates of 12-month secondary patency were 74% (95% CI, 68-80) and 61% (95% CI, 51-71) for vonapanitase and placebo (P = .048). The proportions of vonapanitase and placebo patients were 39% and 25% (P = .035) with unassisted use for hemodialysis and 64% and 44% (P = .006) with unassisted plus assisted use. CONCLUSIONS: Vonapanitase treatment did not significantly improve primary patency but was associated with increased secondary patency and use for hemodialysis. Further research is needed to evaluate these end points.

Salvianolic acid B as an anti-emphysema agent II: In vivo reversal activities in two rat models of emphysema.

Emphysema progressively destroys alveolar structures, leading to disability and death, yet remains irreversible and incurable to date. Impaired vascular endothelial growth factor (VEGF) signaling is an emerging pathogenic mechanism, thereby proposing a hypothesis that VEGF stimulation/elevation enables recovery from alveolar structural destruction and loss of emphysema. Our previous in vitro study identified that salvianolic acid B (Sal-B), a polyphenol of traditional Chinese herbal danshen, stimulated lung cell proliferation and migration, and protected against induced lung cell death, by virtue of signal transducer and activator of transcription 3 (STAT3) activation and VEGF stimulation/elevation. Thus, this study examined Sal-B for in vivo therapeutic reversal of established emphysema in two rat models. Emphysema was induced with porcine pancreatic elastase (PPE) and cigarette smoke extract (CSE), and established by day 21. Sal-B was then spray-dosed to the lung three times weekly for three weeks. Functional treadmill exercise endurance; morphological airspace enlargement and alveolar destruction; apoptosis, cell proliferation and tissue matrix proteins; phosphorylated STAT3 (pSTAT3) and VEGF expressions; neutrophil accumulation; and lipid peroxidation were determined. In both models, Sal-B at 0.2 mg/kg significantly reversed impaired exercise endurance by 80 and 64%; airspace enlargement [mean linear intercept (MLI)] by 56 and 67%; and alveolar destructive index (%DI) by 63 and 66%, respectively. Induced apoptosis activity [cleaved caspase-3] was normalized by 94 and 82%; and cell proliferation activity [proliferative cell nuclear antigen (PCNA)] was stimulated by 1.6 and 2.1-fold. In the PPE-induced model, Sal-B reduced induction of lung's matrix metalloproteinase (MMP)-9 and MMP-2 activities by 59 and 94%, respectively, and restored pSTAT3 and VEGF expressions to the healthy lung levels, while leaving neutrophil accumulation unchecked [myeloperoxidase (MPO) activity]. In the CSE-induced model, Sal-B elevated pSTAT3 and VEGF expressions both by 1.8-fold over the healthy lung levels, and normalized induced lipid peroxidation [malondialdehyde (MDA) activity] by 68%. These results provide an in vivo proof-of-concept for Sal-B as one of the first anti-emphysema agents enabling reversal of alveolar structural destruction and loss via local lung treatment by virtue of its STAT3 activation and VEGF stimulation.

Varenicline is a smoking cessation drug that blocks alveolar expansion in mice intratracheally administrated porcine pancreatic elastase.

Smoking cessation is the most effective treatment in patients with emphysema and lung inflammation. The aim of the present study was to examine the effect of varenicline, a smoking cessation drug, on emphysema in porcine pancreatic elastase (PPE)-inhaled mice. PPE-inhaled mice were treated with varenicline and an α7 nicotinic acetylcholine receptor (nAChR) antagonist, methyllycaconitine (MLA) for 5 and 21 days. Varenicline markedly ameliorated alveolar expansion and inflammatory response in bronchoalveolar lavage fluid in PPE-inhaled mice. These blocking effects were inhibited by MLA. Our findings demonstrate that varenicline likely has an anti-inflammatory property including reduced inflammatory cell recruitment in lung tissue to protect PPE-induced alveolar expansion via α7 nAChR.

Rabbit aortic aneurysm model with enlarging diameter capable of better mimicking human aortic aneurysm disease.

The self-healing phenomenon can be found in the elastase-induced abdominal aortic aneurysm (AAA) model, and an enlarging AAA model was successfully induced by coarctation. Unfortunately, aortic coarctation in these enlarging models is generally not found in human AAA disease. This study aimed to create an experiment model of enlarging AAA in rabbits to better mimic human aortic aneurysm disease. Eighty-four male New Zealand white rabbits were randomly divided into three equal groups: two aneurysm groups (A and B) and a SHAM group. Aneurysm group rabbits underwent extrinsic aortic stenosis below the right renal artery and received a 10-minute incubation of 60 µl elastase (1 unit/µl). Absorbable suture was used in Group A and nonabsorbable cotton thread was used in Group B. A sham operation was performed in the SHAM group. Aortic diameter was measured after 1, 3, 7, and 15 weeks; thereafter animals were sacrificed for histopathological, immunohistochemical and quantitative studies. Two rabbits died at 29 and 48 days, respectively, after operation in Group B. All aneurysms formed and enlarged progressively by 3 weeks in the Aneurysm groups. However, diameter enlargement in Group A was significantly lower than that in Group B at 7 weeks. Aneurysm groups developed intimal hyperplasia; intima-media thickness (IMT) increased significantly by week 7, and aortic media thickness and intima-media ratio (IMR) increased significantly by week 15. Marked destruction of elastin fibers and smooth muscle cells (SMCs) occurred 1 week later and increased progressively thereafter. Intimal hyperplasia and SMCs content in Group A increased significantly by week 15 compared with Group B. Aneurysm groups exhibited strong expression of matrix metalloproteinases 2 and 9 and RAM11 by week 1, and decreased progressively thereafter. In conclusion, this novel rabbit AAA model enlarges progressively without coarctation and is capable of better mimicking human aortic aneurysm disease.

Transient Exocrine Pancreatic Insufficiency: First Report of an Unrecognized Complication of Cytoreductive Surgery and HIPEC.

BACKGROUND: As cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are being increasingly adopted as the standard treatment for peritoneal surface malignancies, familiarity with this procedure's adverse events is also growing. Herein, we describe an unreported adverse event of exocrine pancreatic insufficiency (EPI) following CRS and HIPEC. PATIENTS AND METHODS: Patients who underwent CRS and HIPEC between 9/2016 and 9/2017 were prospectively recruited. Fecal elastase-1 (FE1) and Clostridium difficile toxins were tested in all patients in the immediate postoperative period. Patients with diarrhea who had low FE1 were started on oral pancreatic enzyme replacement therapy (PERT) and their symptomatic progression was followed. RESULTS: A total of 26 patients were included. Eleven patients (42.31%) developed postoperative refractory diarrhea, nine of whom had a low FE1 level. These patients were treated with PERT either directly or after completion of antibiotics course if C. difficile toxin was positive. Eight patients demonstrated symptomatic resolution of their diarrhea, and thus the diagnosis of EPI was established (30.77%). Patients with diarrhea had lower FE1 levels, and were more likely to have had a terminal ileum resection and had a longer hospital stay. Regression analysis identified the rapid rise of a patient's core temperature by >1°C within 15 minutes as the sole predictor of EPI occurrence. CONCLUSION: EPI is a potential adverse event following CRS and HIPEC and might be largely responsible for refractory diarrhea. In our patients with refractory diarrhea and low FE1, PERT provided immediate symptomatic relief. The biological basis of this phenomenon remains unclear and warrants further investigation.

Inhibition of Phosphatidylinositol 3-kinease suppresses formation and progression of experimental abdominal aortic aneurysms.

Accumulating evidence suggests an important role of Phosphatidylinositol 3-kinease (PI3K) pathway in inflammatory cells infiltration. Given the essential role of inflammatory cells infiltration during the formation and progression of abdominal aortic aneurysm (AAA), to investigate the possibility of preventing AAA formation and progression via targeting PI3K is anticipated. Here, experimental AAAs was created in rats by transient intraluminal porcine pancreatic elastase (PPE) infusion into the infrarenal aorta firstly. AAAs rats were administrated with vehicle or Wortmannin during the period of day 0 to day 28 after PPE infusion. The aortic diameter of rats treated with Wortmannin was significantly smaller than those treated with vehicle. Meanwhile, Elastin destruction score and SMC destruction score were significantly decreased in rats treated with Wortmannin. Furthermore, histological analysis revealed infiltration of inflammatory cells were significantly reduced in rats treated with Wortmannin. Finally, the mRNA expression of PI3K and protein expression of pAKT in human abdominal aneurismal aorta tissues was elevated as compare to normal aorta. Our study revealed that PI3K inhibitor suppresses experimental AAAs formation and progression, through mechanisms likely related to impairing inflammation cells infiltration and median elastin degradation. These findings indicated that PI3K inhibitor may hold substantial translation value for AAA diseases.

Hyperpolarized gas diffusion MRI of biphasic lung inflation in short- and long-term emphysema models.

During lung inflation, airspace dimensions are affected nonlinearly by both alveolar expansion and recruitment, potentially confounding the identification of emphysematous lung by hyperpolarized helium-3 diffusion magnetic resonance imaging (HP MRI). This study aimed to characterize lung inflation over a broad range of inflation volume and pressure values in two different models of emphysema, as well as in normal lungs. Elastase-treated rats (n = 7) and healthy controls (n = 7) were imaged with HP MRI. Gradual inflation was achieved by incremental changes to both inflation volume and airway pressure. The apparent diffusion coefficient (ADC) was measured at each level of inflation and fitted to the corresponding airway pressures as the second-order response equation, with minimizing residue (χ2 < 0.001). A biphasic ADC response was detected, with an initial ADC increase followed by a decrease at airway pressures >18 cmH2O. Discrimination between treated and control rats was optimal when airway pressure was intermediate (between 10 and 11 cmH2O). Similar findings were confirmed in mice following long-term exposure to cigarette smoke, where optimal discrimination between treated and healthy mice occurred at a similar airway pressure as in the rats. We subsequently explored the evolution of ADC measured at the intermediate inflation level in mice after prolonged smoke exposure and found a significant increase (P < 0.01) in ADC over time. Our results demonstrate that measuring ADC at intermediate inflation enhances the distinction between healthy and diseased lungs, thereby establishing a model that may improve the diagnostic accuracy of future HP gas diffusion studies.

rHuKGF ameliorates protease/anti-protease imbalance in emphysematous mice.

We attempted to elucidate the beneficial role of rHuKGF supplementation in the amelioration of protease/antiprotease imbalance and TGF-ß1 signaling pathway leading to alveolar tissue maintenance in elastase induced emphysematous mice. Thirty two male C57BL mice were divided into four groups i.e. control, emphysema, therapy and rHuKGF only and were oropharyngeally instilled with saline/porcine pancreatic elastase/rHuKGF. Subsequently, lungs from mice were collected for histopathology and molecular biology studies. rHuKGF supplementation significantly ameliorated the mRNA expressions of CRP, TNF-α, MMP-2, MMP-7, MMP-8, MMP-9, MMP-12, A1AT, TIMP1, TIMP2, PCNA, Ki67, SPB, SPC and PdPn. MMP-2 and TIMP-1 enzyme activity was resolved due to rHuKGF. Likewise, due to rHuKGF supplementation the protein expressions of CRP, MMP2, MMP7, MMP8 & CTSE, SERPINE1, SERPINA1, TIMP4, GSTA1, HDAC3, PCNA, CDH1, SP-B & SP-C were ameliorated. Moreover, the mRNA expressions of overall TGFß-1 pathway was also significantly ameliorated due to rHuKGF supplementation. Lung histopathology represents recovery of lost alveolar septa due to rHuKGF supplementation. Moreover, positive DAB staining of PCNA, SP-B & SP-C was observed due to rHuKGF supplementation at tissue level. rHuKGF is therapeutically potent in maintaining pulmonary tissue integrity by amelioration of protease/antiprotease imbalance and TGFß-1 pathway in emphysema.