Changes in the levels of free sialic acid during ex vivo lung perfusion do not correlate with pulmonary function. Experimental model.

Background: Ex vivo lung perfusion (EVLP) constitutes a tool with great research potential due to its advantages over in vivo and in vitro models. Despite its important contribution to lung reconditioning, this technique has the disadvantage of incurring high costs and can induce pulmonary endothelial injury through perfusion and ventilation. The pulmonary endothelium is made up of endothelial glycocalyx (EG), a coating of proteoglycans (PG) on the luminal surface.

Clinical, Histological, and Profibrotic Extracellular Matrix Protein Changes in a Model of Tracheal Stenosis Induced by Cervical Tracheal Autotransplantation.

Background: Tracheal stenosis (TS) is a complication of prolonged intubation, tracheotomy, and tracheal surgery that compromises the vascular supply. Animal models are essential for studying its pathophysiology and the effect of interventions.

Objective: To establish a TS model in rats secondary to tracheal autotransplantation with a graft submerged in bleomycin (Atx-Bleo).

Endothelin-Converting Enzyme 1 and Vascular Endothelial Growth Factor as Potential Biomarkers during Lung Perfusion with Prolonged Hypothermic Lung-Sparing.

Lung transplantation requires optimization of donor's organ use through ex vivo lung perfusion (EVLP) to avoid primary graft dysfunction. Biomarkers can aid in organ selection by providing early evidence of suboptimal lungs during EVLP and thus avoid high-risk transplantations. However, predictive biomarkers of pulmonary graft function such as endothelin-converting enzyme (ECE-1) and vascular endothelial growth factor (VEGF) have not been described under EVLP with standard prolonged hypothermic preservation, which are relevant in situations where lung procurement is difficult or far from the transplantation site.

In vivo performance of decellularized tracheal grafts in the reconstruction of long length tracheal defects: Experimental study.

Background: The repair of long-segment tracheal lesions remains an important challenge. Nowdays no predictable and dependable substitute has been found. Decellularized tracheal scaffolds have shown to be a promising graft for tracheal transplantation, since it is non-immunogenic.

Experimental Tracheal Replacement: Angiogenesis and Null Apoptosis Promote Stenosis.

Background: Tracheal replacement is a challenge for thoracic surgeons due to stenosis in the trachea-prosthesis anastomosis. We propose that stenosis occurs due to fibrosis as a result of an abnormal healing process, characterized by an increased expression of wound healing growth factors (vascular endothelial growth factor [VEGF], survivin, and CD31), which promote angiogenesis and decrease apoptosis. We analyzed the immunoreactivity of VEGF, survivin, CD31, and caspase-3 in the development of fibrotic stenosis in prosthetic tracheal replacement.

Treatment with Hyaluronic Acid and Collagen-Polyvinylpyrrolidone Improves Extracellular Matrix Assembly for Scarring after Tracheal Resection.

Treatment of tracheal stenosis is occasionally performed in combination with wound healing modulators to manipulate new extracellular matrix (ECM) formation and prevent fibrosis. Hyaluronic acid (HA) and collagen-polyvinylpyrrolidone (collagen-PVP) decrease fibrosis in experimental tracheal healing. However, they have not been used clinically as their effect on ECM components, which modify tracheal scarring, has not been described.

Expression of Claudin-4 in Lung Ischemia-Reperfusion Injury in Experimental Lung Transplantation.

Objective: To assess the presence of CLDN4 in bronchoalveolar lavage fluid (BALF) and pulmonary tissue as an early indicator of LIRI and its relationship with changes in pulmonary physiology, edema formation and histology in an experimental porcine model of LTx with CIT of 50 min or 6 h.

Methods: In 12 pigs, LIRI was produced by: group I ( = 6) LTx with 50 min of CIT (LTx-50 min-CIT); and group II ( = 6) LTx with 6 h of CIT (LTx-6h-CIT). The lung function, edema formation, macroscopic and microscopic changes were assessed.

Effects of Pirfenidone and Collagen-Polyvinylpyrrolidone on Macroscopic and Microscopic Changes, TGF-1 Expression, and Collagen Deposition in an Experimental Model of Tracheal Wound Healing.

Tracheal stenosis (TS) is a fibrosis originated by prolonged inflammation and increased transforming growth factor beta 1 (TGF-1) expression and collagen deposition (CD) in the tracheal wound. Several wound-healing modulators (WHMs) have been used to modulate the tracheal healing process and prevent TS, but they have failed, justifying the need to evaluate alternative WHM. The pirfenidone (PFD) and collagen-polyvinylpyrrolidone (Collagen-PVP) decrease inflammation and fibrosis.

Lyophilized allografts without pre-treatment with glutaraldehyde are more suitable than cryopreserved allografts for pulmonary artery reconstruction.

Various methods are available for preservation of vascular grafts for pulmonary artery (PA) replacement. Lyophilization and cryopreservation reduce antigenicity and prevent thrombosis and calcification in vascular grafts, so both methods can be used to obtain vascular bioprostheses. We evaluated the hemodynamic, gasometric, imaging, and macroscopic and microscopic findings produced by PA reconstruction with lyophilized (LyoPA) grafts and cryopreserved (CryoPA) grafts in dogs.

Respiratory mechanics and plasma levels of tumor necrosis factor alpha and interleukin 6 are affected by gas humidification during mechanical ventilation in dogs.

The use of dry gases during mechanical ventilation has been associated with the risk of serious airway complications. The goal of the present study was to quantify the plasma levels of TNF-alpha and IL-6 and to determine the radiological, hemodynamic, gasometric, and microscopic changes in lung mechanics in dogs subjected to short-term mechanical ventilation with and without humidification of the inhaled gas. The experiment was conducted for 24 hours in 10 dogs divided into two groups: Group I (n = 5), mechanical ventilation with dry oxygen dispensation, and Group II (n = 5), mechanical ventilation with oxygen dispensation using a moisture chamber.

[Effects of propofol pretreatment on endothelin in oleic acid-induced acute lung injury].

Introduction: Acute lung injury (ALI) is a pathological condition characterized by injury in the alveolar-capillary membrane that triggers local and systemic inflammation. Endothelin (ET) is a protein that regulates immune response and constricts blood vessels; when it is over-expressed, it may contribute to high blood pressure and lung injury. This work tries to determine if propofol may decrease hemodynamic, gasometric, microscopic, ET-1 plasmatic concentration, and immuno-histochemical alterations in an experimental model of oleic acid-induced acute lung injury.

Canine tracheal cartilage cryopreservation: freezing injury is not related to caspase-3 expression.

Currently, there are no surgical strategies to treat tracheal lesions longer than 7 cm. Such patients are not candidates for tracheal resection or end-to-end anastomosis and are thus left with only repeated palliative procedures to relieve their respiratory insufficiency. Experimental studies using cryopreserved trachea have produced contradictory results, limiting the clinical application of this technique.

[Glutaraldehyde-preserved and lyophilized bovine pericardium as materials for medialization of the vocal folds in an animal model].

Introduction: Glutaraldehyde-preserved bovine pericardium (GBP) and lyophilized GBP (LGBP) have been used successfully in repairing several anatomical defects, but their effectiveness and safety as implants to vocal cords (VC) have not been reported.

Objective: The aim of this study was to evaluate the use of GBP and LGBP as materials for medialization thyroplasty, as well as to assess the endoscopic, macroscopic and microscopic VC changes after medialization in an experimental canine model.

Material And Methods: In 12 healthy mongrel dogs, the right VC were medialized using pericardium and the left with polytetrafluoroethylene (PTFE).

[Experimental model of canine oleic acid-induced acute lung injury: establishment of a working model].

Introduction: There are several experimental model of acute lung injury induced by oleic acid (OA); however, there are few studies that show how this injury develops.

Objective: This study seeks to detail the x-ray, hemodynamic, gasometrical, gravimetrical, macroscopic and microscopic alterations developed in an experimental model of canine OA-induced acute lung injury (ALI).

Material And Methods: Twelve dogs were divided in 2 study groups: Group I (n=6): Control group without ALI.

[Middle ear packing with collagen-polyvinylpyrrolidone sponge. Experimental study in guinea pigs].

Introduction: Packing material is mandatory in middle ear (ME) surgery in order to avoid inflammation, adhesions and fibrotic healing. Collagen polivynil-pirrolidone (CPVP) is a healing modulator, which reduces inflammation and fibrosis. Hence we can hypothesize that packing of the ME with CPVP sponge will lead a good ME healing.

Tracheal cryopreservation: caspase-3 immunoreactivity in tracheal epithelium and in mixed glands.

Cryopreservation has an immunomodulating effect on tracheal tissue as a result of class II antigen depletion due to epithelium exfoliation. However, not all epithelium is detached. We evaluated the role of apoptosis in the remaining epithelium of 30 cryopreserved tracheal grafts.

Wound healing modulators in a tracheoplasty canine model.

Postsurgical tracheal stenosis results from fibrosis formation due to ischemia. There are healing modulators, hyaluronic acid (HA) and collagen polyvinylpyrrolidone (CPVP), which reduce collagen fibers formation. Thus we can hypothesize that the topical application of one of these modulators can diminish postsurgical tracheal scarring and stenosis.

Cryopreserved tracheal grafts: a review of the literature.

Cryopreserved tracheal grafts have been used in several experimental models of long segment replacement. The clinical application of the procedure has been limited due to the fact that contradictory results have been reported. The purpose of this article is to present a review of the literature on tracheal cryopreservation.

[Effect of the hyaluronic acid on tracheal healing. A canine experimental mode].

Several drugs have been used to modulate of the tracheal healing process in order to prevent tracheal stenosis. Hyaluronic acid (HA) is a modulator of the fibrogenesis. In this work we evaluate the effect in order the application of hyaluronic acid has on tracheal healing, after cervical tracheoplasty in dogs.

Usefulness of bovine pericardium as interpositional graft in the surgical repair of nasal septal perforations (experimental study).

A 2.5-cm nasal septal perforation was performed in 18 pigs and repaired as follows: group I (n = 6), septal perforation without treatment; group II (n = 6), surgical repair with interpositional graft of glutaraldehyde-preserved bovine pericardium (GPBP); group III (n = 6), surgical repair with interpositional graft of lyophilized GPBP (LGPBP). The animals were evaluated clinically and radiologically (x-ray and CT scan) 2 days before surgery, daily during the first postoperative week, and weekly during the next 6 months.

[Evaluation of the use of bovine pericardium in non-anatomical lung resections in dogs].

Unlabelled: In this study we assessed the usefulness, healing, as well as the integration to lung tissue of glutaraldehyde preserved at 0.5% bovine pericardium GPBP and lyophilized (GPBPL), after reinforced resection of lung tissue in dogs by thoracotomy or thoracoscopy.

Material And Methods: GPBP and GPBPL were prepared and used to reinforce the suture line of lung resection in 30 mongrel dogs: Group I (n = 6): The GPBP were fixed on the lung with 4-0 polypropylene by thoracotomy.

Effect of perfusion and preservation on IL1-beta, IL-6, and IL-10 production in murine lung.

We evaluated the production of the interleukins (ILs) IL-1beta, IL-6, and IL-10 in both the vasculature and pulmonary tissue before and after 24 h of lung preservation. The cardiopulmonary blocs of 21 Balb-c mice were divided into three study groups (7 mice/group) and were flushed through the pulmonary artery with Krebs-Henseleit buffer (K-Hb) at 4 degrees C at a rate of 0.2 mL/min as follows: Group 1, lung washout: lungs were flushed until pulmonary effluent was clear.

Suture-line reinforcement with glutaraldehyde-preserved bovine pericardium for nonanatomic resection of lung tissue.

In this study we assessed the usefulness of glutaraldehyde-preserved bovine pericardium (GPBP), preparated in our laboratory, in nonanatomic resection of lung tissue in dogs. A 30% resection of the right cranial lobe of the lung was performed in 18 mongrel dogs. The suture line was reinforced with GPBP strips.