João Gabriel Roderjan

Decellularized heterografts versus cryopreserved homografts: experimental study in sheep model

OBJECTIVES The aim of this study is to assess the biological behaviour of porcine decellularized heterografts (Desc group) compared with cryopreserved homografts (Crio group) implanted in juvenile sheep. METHODS Decellularized porcine pulmonary heterografts were implanted in five animals and cryopreserved pulmonary homografts in another five. The animals were followed-up for a mean of 280 +/- 14 days. The valve diameter was measured by echocardiography, which was performed at the 30th postoperative day, and before the explantation. The valves were also assessed macroscopically. Histological evaluation was performed using H.E., Gomori and Weigert staining. Immunohistochemistry specified different cell types (Factor VIII, CD3, Vimentin and CD68). Calcium quantity was analyzed using atomic absortion spectometry. RESULTS There was one death in the Desc group due to endocarditis. The valves of Crio group showed decrease in the cellularity whereas the valves of Desc group showed matrix repopulation with endothelial and interstitial cells. Loss of collagen density and disarrangement of the normal fiber architecture was observed in Crio group. Calcium content demonstrated higher levels on the cusps and conduits in Crio group comparatively with Desc group. (P=0.016). The mean valvular diameter at the explantation was significantly increased (P=0.025) in the Desc group. CONCLUSIONS Decellularized heterografts had a different biological behaviour when compared to cryopreserved homografts and become repopulated by cells with fibroblasts and endothelial cells characteristics. The matrix was preserved and some regenerative potential was present.

Evaluation of the biological behavior of decellularized pulmonary homografts: an experimental sheep model

INTRODUCTION The cryopreserved homograft is a good valve substitute due attributes like excellent hemodynamics, low incidence of thromboembolic events, infection resistance and good mid-term durability. However, progressive homograft degeneration and fibrocalcification may occur, particularly in the childhood and young adults. Their antigenicity triggers an immunological reaction that plays an important role in their degeneration and failure. The decellularization process was proposed to decrease this antigenicity. By the action of detergents and enzymes, this process removes all cellular components from the homograft matrix, diminishing immunogenicity and probably delaying its degeneration. OBJECTIVE The objective of this experimental and descriptive study is to evaluate the biological and functional behavior of decellularized pulmonary homografts (Decell-H), treated by a sodium dodecil sulfate solution (0.1%), developed in our University (Pontifícia Universidade Católica do Paraná). For the characterization of Decell-H performance, parameters like recellularization, calcification, and echocardiographic data will be analyzed. METHODS Eight juvenile sheep were submitted to the implantation of the Decell-H sutured into orthotopic position, through a left thoracotomy and with cardiopulmonary bypass support. They were followed-up clinically and by periodical echocardiograms until the explantation, which were performed in different time for every two sheep: seven, 30, 90 and 180 postoperative days. For histological analysis we used Hematoxilin-eosin, Movat and Alizarin-Red staining. RESULTS The sheep reached their follow-up period in a good clinical state. There was no valve regurgitation or stenonis by the echocardiogram. The animals submitted to the explantation in 90 and 180 days had a significant somatic growth and these Decell-H(s) had a diameter increase, without central valve insufficiency. Histologically, all homografts preserved their extra-cellular matrix organization and were progressively recellularized, without calcification. CONCLUSION In this experimental model, the Decell-H behaved as an excellent valve substitute.

20 years experience with the Ross operation in middle-aged patients: the autologous principle is still alive

Objectives Review our long-term results with the Ross operation in middle-aged patients. Methods Between 1995 and 2016, 129 consecutive patients (106 males); mean age (47.2 ± 5.2 years) underwent a Ross operation. Right ventricular outflow tract (RVOT) reconstruction was performed with cryopreserved (n = 45) or decellularized allografts (n = 84). Mean follow-up was 8.4 ± 5.3 years (0.1 20.5 years). We analyzed early and late mortality, as well as valve related events and the need for reoperations. Results Early mortality was 1.6% and late survival was 87.6% at 16 years. There were 4 reoperations on the pulmonary autograft (96% freedom at 16 years) and 2 on the pulmonary allografts (99% freedom at 16 years). The 16-year freedom from more than mild aortic insufficiency (AI) and a late root diameter >45 mm was 64% and 71%, respectively. Patients with the preoperative diagnosis of AI are at greater risk for these complications. Among the allografts, decellularized allografts showed superior freedom from structural valve dysfunction. Conclusions The Ross operation in this cohort was associated with long-term survival similar to the general population and low incidence of reoperations. Patients with the preoperative diagnosis of AI are at increased risk for late autograft insufficiency and root dilatation. Decellularized allografts presented the best results for reconstruction of the RVOT. These results support the conclusion that the Ross operation has an important role in the treatment of middle-aged patients with aortic valve disease, especially those with pure aortic stenosis.

Decellularization as an anticalcification method in stentless bovine pericardium valve prosthesis: a study in sheep

OBJECTIVE The objective was to analyze the decellularization process with SDS in glutaraldehyde-preserved bovine pericardium as an anticalcification method in a circulatory sheep model. METHODS The valved tubs were implanted in pulmonary artery position in sheep by 180 days. The animals were divided in two groups of 8 animals: control group--glutaraldehyde-preserved bovine pericardium and the study group--decellularized bovine pericardium with 0,1% SDS and glutaraldehyde-preserved. After explantation the tubs were analized by x-ray macroscopy, hematoxilin-eosin, alizarin-red and Russel-Movatz pentacromic histology. The calcium content was measured by flame atomic absorption spectrometry. RESULTS There was no early mortality, but two animals in each group died during the study. All cusps in the control group were severely calcified and in some points in the conduits, while the decellularized group did not show macroscopic calcification. Data were proved by x-ray and histologycal exams. The matrix was preserved in histologycal analysis in decellularized group, without gross calcification. The wall conduits calcium content was 35,25 ± 42,13 µg/mg in the control group versus 15,75 ± 10,44 µg/mg in the decellularized one: in the cusps was 264,4 ± 126,16 µg/mg in control group versus 94,29 ± 27,05 µg/mg in decellularized group (P = 0,009). CONCLUSION The decellularization with 0.1% SDS was effective as an anticalcification method in bovine pericardial grafts implanted in a sheep circulatory model for 180 days.

Effect of SDS-based decelullarization in the prevention of calcification in glutaraldehyde-preserved bovine pericardium: study in rats

OBJECTIVE The aim of study was to investigate the SDS-based decellularization process as an anticalcification method in glutaraldehyde-preserved bovine pericardium in subcutaneous rat model. METHODS Pericardium samples with 0.5 cm² area were divide in four groups: group GDA: 0.5% glutaraldehyde-preserved pericardium (GDA); group GDA-GL: GDA + 0.2% glutamic acid (GL); group D-GDA: decellularized (D) pericardium with 0.1% SDS + GDA and group D-GDA-GL: decellularized pericardium + GDA + 0.2% glutamic acid. After this samples were implanted in 18 rats in subcutaneous position till 90 days. Each animal received samples of the four groups. The explants were performed at 45 and 90 days. The explants were subjected to histology in glass slides stained with hematoxilin-eosin and alizarin red, morphometry evaluation and the calcium content was measured by flame atomic absorption spectrometry. RESULTS The inflammatory infiltrate was the same in all groups, however more intense in GDA and GDA-GL groups in 45 days, increasing at 90 days. The calcium contents for 45 days were: 32.52 ± 3.19 µg/mg in GDA group; 22.12 ± 3.87 µg/ mg in GDA-GL group; 1.06 ± 0.38 µg/mg in D-GDA group and 3.99 ± 5.78 µg/mg in D-GDA-GL (P< 0.001). For 90 days were 65.91 ± 24.67 µg/mg in GDA group; 38.37 ± 13.79 µg/mg in GDA-GL group; 1.24 ± 0.99 µg/mg in D-GDA group and 30.54 ± 8.21 µg/mg in D-GDA-GL (P< 0.001). Only D-GDA did not show increase rates of calcium at 45 to 90 days (P=0.314). CONCLUSION SDS-based decellularization process reduced the inflammatory intensity and calcification in bovine pericardium in subcutaneous rat model for 90 days.Objective: The aim of this study was to investigate the SDS-based decellularization process as an anticalcification method in glutaraldehyde-preserved bovine pericardium in subcutaneous rat model. Methods: Pericardium samples with 0.5 cm 2 area and divided into four groups: GDA group: 0.5% glutaraldehydepreserved pericardium (GDA); GDA-GL group: GDA + 0.2% glutamic acid (GL); D-GDA group: decellularized (D) pericardium with 0.1% SDS + GDA, and D-GDA-GL group: decellularized pericardium + GDA + 0.2% glutamic acid. Afterwards these samples were implanted in 18 rats in subcutaneous position up to 90 days. Each animal received samples of the four groups. The explants were performed at 45 and 90 days. The explants were subjected to histology in glass slides stained with hematoxilin-eosin and alizarin red, morphometry evaluation and the calcium content was measured by flame atomic absorption spectrometry. Results: The standard of inflammatory infiltrate was the same in all groups, however more intense in GDA and GDAGL groups in 45 days, increasing at 90 days. The calcium contents for 45 days were: 32.52 ± 3.19 µg/mg in GDA group; 22.12 ± 3.87 µg/mg in GDA-GL group; 1.06 ± 0.38 µg/mg in D-GDA group and 3.99 ± 5.78 µg/mg in D-GDA-GL (P< 0.001). For 90 days were 65.91 ± 24.67 µg/mg in GDA group; 38.37 ± 13.79 µg/mg in GDA-GL group; 1.24 ± 0.99 µg/mg in D-GDA group and 30.54 ± 8.21 µg/mg in D-GDA-GL (P< 0.001). Only D-GDA did not show increase rates of calcium at 45 to 90 days (P=0.314). Conclusion: SDS-based decellularization process reduced the inflammatory intensity and calcification in bovine pericardium in subcutaneous rat model for 90 days.

In vitro evaluation of bovine pericardium after a soft decellularization approach for use in tissue engineering: XXXX

Pericardial membrane derived from bovine heart tissues is a promising source of material for use in tissue‐engineering applications. However, tissue processing is required for its use in humans due to the presence of animal antigens. Therefore, the purpose of this study was to evaluate the structural integrity and biocompatibility of the bovine pericardium (BP) after a soft decellularization process with a 0.1% sodium dodecyl sulfate (SDS) solution, with the aim to remove xenoantigens and preserve extracellular matrix (ECM) bioactivity. The decellularization process promoted a mean reduction of 77% of the amount of DNA in the samples in which cell nuclei staining was undetectable. The ECM content was maintained as mostly preserved after decellularization as well as its biomechanical properties. In addition, the decellularization protocol has proven to be efficient in removing the xenoantigen alpha‐gal, which is responsible for immune rejection. The decellularized BP was noncytotoxic in vitro and allowed human adipose‐derived stem cell (hASC) adhesion. Finally, after 7 days in culture, the tissue scaffold became repopulated by hASCs, and after 30 days, the ECM protein pro‐collagen I was seen in the scaffold. Together, these characteristics indicated that soft BP decellularization with 0.1% SDS solution allows the acquirement of a bioactive scaffold suitable for cell repopulation and potentially useful for regenerative medicine.

Conventional culture method and qPCR using 16S rDNA for tissue bank: a comparison using a model of cardiac tissue contamination

Real-time polymerase chain reaction (qPCR) using 16S rDNA is an alternative to conventional culture-based tests. The aim of this study was to compare the conventional culture method with qPCR using 16S rDNA in a model of cardiac tissue contamination. Samples of cardiac tissue for artificial contamination with Escherichia coli and control samples were submitted for DNA extraction, which was conducted by selective and alkaline lysis and purification steps. A standard curve for 16S rDNA was constructed to determine the efficiency and analytical sensitivity of the assay in concentrations from 106 to 102 c.f.u. ml-1 using TaqMan Master Mix. 16S rDNA was detected in all contaminated samples; however, it was not detected in the the final washing step solution of the sample with a bioburden of 102 c.f.u. ml-1. Using qPCR is a potential alternative to conventional culture for microbiological safety testing of allograft tissues for biobanking, reducing the time and labour input required.

Eficácia do AlCl3 e etanol na prevenção da calcificação de fragmentos da parede aórtica porcina fixados em GDA

OBJECTIVE: To evaluate the efficiency of aluminum chloride in isolation or associated with ethanol to prevent calcification and inflammatory reaction with fragments of porcine aortic wall fixed in glutaraldehyde (GDA) and subdermally implanted in young rats. METHOD: Fifteen Sprague-Dawley rats were studied. Three fragments of porcine aortic wall were implanted in the subdermal tissue. The fragments were previously subjected to three different methods of treatment: I (GDA), II (GDA + aluminum), III (GDA + ethanol + aluminum). Explantation was performed after fifteen, thirty and sixty days. Histological analysis was achieved using hematoxylin & eosin (HE) and alizarin-red at pHs of 4.2 and 7.0. Calcium content was determined by atomic absorbance spectroscopy. RESULTS: HE and alizarin red staining showed that the aortic wall extracellular matrix was best preserved in the fragments of Group III. The intensity of the inflammatory reaction was lower in this group. When stained with alizarin red at pH 4.2, Groups II and III had lower degrees of calcification compared with Group I. With alizarin red staining at pH 7.0, Group III demonstrated less calcification compared with Groups I and II. Atomic absorbance spectroscopy showed similar calcium levels for both Groups II and III, but significantly less than in Group I. CONCLUSION: Treatment with aluminum chloride inhibits calcification of fragments of aortic wall after implantation and reduces inflammatory reaction. The combined use of ethanol with aluminum chloride is more efficient to inhibit calcification and also to diminish inflammatory reaction.