Glutaraldehyde-preserved Bovine Pericardium Research Articles

Enhanced vascular biocompatibility of decellularized xeno-/allogeneic matrices in a rodent model.

Glutaraldehyde preservation is the gold standard for cardiovascular biological prosthesis. However, secondary calcifications and the absence of tissue growth remain major limitations. Our study assessed in vitro and in vivo the biocompatibility of human (fascia lata, pericardium) and porcine tissues (pericardium, peritoneum) treated with a physicochemical procedure for decellularization and non-conventional pathogens inactivation. Biopsies were performed before and after treatment to assess decellularization (HE/Dapi staining/DNA quantification/MHC I/alpha gal immunostaining) and mechanical integrity. Forty-five rats received an abdominal aortic patch of native cryopreserved tissues (n=20), treated tissues (n=20) or glutaraldehyde-preserved bovine pericardium (GBP, control, n=5). Grafts were explanted at 4weeks and processed for HE/von Kossa staining and immunohistochemistries for lymphocytes (CD3)/macrophages (CD68) histomorphometry. 95% of decellularization was obtained for all tissues except for fascia lata (75%). Mechanical properties were slightly altered. In the in vivo model, a significant increase of CD3 and CD68 infiltrations was found in native and control implants in comparison with decellularized tissues (p<0.05). Calcifications were found in 3 controls. Decellularized tissues were recolonized. GBP showed the most inflammatory response. This physicochemical treatment improves the biocompatibility of selected xeno/allogeneic tissues in comparison with their respective native cryopreserved tissues and with GBP. Incomplete decellularization is associated with a significantly higher inflammatory response. Our treatment is a promising tool in the field of tissue decellularization and tissue banking.

Histology of Pericardial Tissue Substitutes Used in Congenital Heart Surgery.

Pericardium is used as a tissue substitute during pediatric heart surgery. However, little is known about the histological characteristics of pericardial tissue substitutes. We searched our clinical and Pathology databases to identify cases in which glutaraldehyde-preserved autologous pericardium, PhotoFix bovine pericardium, or Peri-Guard Repair Patch glutaraldehyde-preserved bovine pericardium was used as patch material during cardiac surgery and in which explanted tissue substitute was available for histologic examination. Tissue sections were stained with hematoxylin and eosin, Masson trichrome, and Movat pentachrome, and were graded for inflammation, tissue substitute degeneration, neointima formation, and calcification. Nonparametric statistical methods were used to test differences between groups because of small sample size. The eight patients who received PhotoFix pericardium were older (median 10 months vs 10 days, P < 0.05) and the material was in situ longer (median 14 vs 2.5 months, P < 0.05) compared to the eight who received autologous pericardium. Only three patients received glutaraldehyde-preserved bovine pericardium precluding statistical comparison. Inflammation and tissue degeneration were greater in PhotoFix pericardium compared to autologous pericardium but were no more than moderate. Neointima formation and calcification did not differ significantly between the two groups. PhotoFix bovine pericardium is associated with more inflammation and material degeneration but calcification, and neointima formation are similar to autologous pericardium. Although the short-term outcomes are acceptable, calcification and degeneration seen in some cases suggest that long-term outcomes and performance at certain anatomic locations need further study.

Short- and mid-term results of xenograft–bovine pericardial patch in the repair of intracardiac defects: final results of a single-centre study

A variety of patch materials have been used in the repair of intracardiac defects. We evaluated the short- and mid-term clinical and echocardiography results of glutaraldehyde-preserved bovine pericardium patches used to repair intracardiac defects in our clinic. This study examines the short- (up to 30 days post-operatively) and mid-term (up to 24 months post-operatively) results of 533 patients with intracardiac defects who underwent surgical correction with glutaraldehyde-preserved bovine pericardium patches between 2004 and 2010 at a university clinic. Short- and mid-term post-operative echocardiographic studies showed no evidence of calcification, thrombus, or aneurysmal dilatation on the patch. Vegetation developed in two (0.37%) of the 533 patients. These results that have been obtained from a group of large number of patients imply that the glutaraldehyde-preserved bovine pericardium patches may be preferable in the closure of cardiac defects because of their low complication rates and ease of use.

Use of Glutaraldehyde-Preserved Bovine Pericardium Patch in Vascular Repair of Portal Vein in a Patient with Pancreatic Cancer

Advanced-stage gastrointestinal tumors are aggressive and frequently invade blood vessels. Advances in endovascular surgery can repair blood vessels that may be infiltrated by a tumor. Currently there are many materials to do this, as the use of prostheses or implants and patches. In Mexico, the bovine pericardium preserved with glutaraldehyde has been used to treat incisional, inguinal, and diaphragmatic hernias and repair vascular defects with good results, low cost, and no allergic reaction from the patient. We report the case of a 47-year-old man, with a history of smoking and alcoholism, diagnosed with pancreatic adenocarcinoma. The tumor, with the use of endoscopic ultrasound, showed direct contact with the portal vein without invading the confluence of the mesenteric vein. During exploratory laparotomy, a tumor attached to the head of the pancreas of 4cm × 4cm was found, with tumor invasion of 1cm × 2cm on the outer sidewall of the portal vein. We performed pylorus-preserving pancreatoduodenectomy and tumor resection of the portal vein wall with placement of glutaraldehyde-preserved bovine pericardium patch to repair it. The intraoperative and immediate postoperative period arose without complications. The patient was discharged with good result and is currently under surveillance. We report this case to show a successful result using glutaraldehyde-preserved bovine pericardium to close vascular defects after resection of the tumor secondary to vascular invasion.

Efeito da descelularização com SDS na prevenção da calcificação em pericárdio bovino fixado em glutaraldeído

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. 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. 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). SDS-based decellularization process reduced the inflammatory intensity and calcification in bovine pericardium in subcutaneous rat model for 90 days.

Descelularização como método anticalcificante em próteses valvares de pericárdio bovino sem suporte

The objective was to analyze the decellularization process with SDS in glutaraldehyde-preserved bovine pericardium as an anticalcification method in a circulatory sheep model. 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. 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). 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.

Lyophilized glutaraldehyde-preserved bovine pericardium for experimental atrial septal defect closure

A variety of patch materials has been used to close large atrial septal defects (ASD). Autologous pericardium and glutaraldehyde-preserved bovine pericardium are the most used. Lyophilized bovine pericardium has not been tested inside the cardiovascular system. The aim of this work was to study the behaviour and effectiveness of lyophilized glutaraldehyde-preserved bovine pericardium in ASD closure. Sixteen mongrel dogs were operated on. A 3 cm diameter atrial septal defect was created, and closed with: Group I (n=8): Lyophilized glutaraldehyde preserved bovine pericardium (LGPBP). Group II (n=8): Vascular Dacron patch. The animals were evaluated clinically, by echocardiography, macroscopically, and microscopically. Statistical analysis was done with analysis of variance (ANOVA) and Student's t-test. All the animals survived the surgical procedure and study time (6 months). Clinically all the animals displayed normal physical activity, with normal cardiac sounds. Echocardiography showed that both groups had a normal heart without intracardiac shunts, no thrombus formation, and no vegetations. Macroscopically all the animals showed good integration of the lyophilized bioprosthesis and Dacron patch. All group I animals presented a decrease of the area of the ASD in the left atrium (p<0.001 by ANOVA and Student's t-test). Microscopically, group I presented dense and well-organized collagenous tissue, areas of cartilaginous metaplasia and remnants of the lyophilized bioprosthesis (p<0.001 by ANOVA and Student's t-test). Group II showed encapsulated Dacron patch covered with collagenous tissue and cartilaginous metaplasia. In conclusion, the new lyophilized bioprosthesis is well integrated into the atrial septum, without complications and is effective for ASD closure.

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. At the end of the study the animals were euthanized with an overdose of pentobarbital. Macroscopic and microscopic examination of the grafts and nasal septum was performed. All the animals survived the surgical procedure. Five pigs in group I showed persistence of the septal perforation. All the animals in groups II and III showed total closure of the septal perforation, with the presence of fibrotic tissue on the pericardial grafts as well as in the septal cartilage, and overall good healing. In conclusion, GPBP and LGPBP are adequate materials that can be used as interpositional grafts in the surgical closure of septal perforations in pigs

Intermediate follow-up of a composite stentless porcine valved conduit of bovine pericardium in the pulmonary circulation

Background. In the pediatric population, glutaraldehyde-preserved bovine pericardium conduit containing a stentless porcine valve has been proposed as an alternative to homografts for right ventricular outflow tract reconstruction. Methods. Between June 1996 and March 2000, a total of 55 patients, 20 with truncus arteriosus, 21 with pulmonary atresia with ventricular septal defect, and 14 with miscellaneous defects, received this conduit. Median age at implantation was 3.4 months (range, 3 days to 19 years), and 27 patients (50%) were less than 3 months old. Clinical outcome, echocardiographic data, and pathologic analysis were recorded. End points for conduit failure were conduit replacement or dilation. A mean follow-up of 27 months (range, 2 to 46 months) was available for 47 survivors. Results. Procedure for conduit obstruction was required in 13 patients. The most common procedure was operation, and all but 3 patients had an unsuccessful balloon angioplasty before reoperation. Actuarial freedom from conduit dilation or reoperation was 93.6% (95% confidence limits, 82% to 99%), 81.9% (95% confidence limits, 64% to 91%), 77.8% (95% confidence limits, 39% to 78%), and 64.3% (95% confidence limits, 26% to 73%) at 1, 2, 3, and 4 postoperative years, respectively. Univariate analysis identified small conduit size as a risk factor for conduit obstruction. Conclusions. Although this new conduit was not free from progressive obstruction, our clinical results (easy to work and good valvular function) and the availability in small sizes encouraged us to use it as an alternative to small-size homografts when those were not available.

Protein adsorption in glutaraldehyde-preserved bovine pericardium and porcine valve tissues

Background. Proteins adsorbed by bioprosthetic tissues after implantation play a major role in the process of calcification. We investigated whether there are differences in protein adsorption between bovine pericardial and porcine valvular tissues that could correlate with the differences observed clinically.Methods. Glutaraldehyde-treated bovine pericardial and porcine valve samples were implanted subcutaneously in rats and retrieved 1 month after implantation. Total protein content was assessed by Lowry’s method. Qualitative analysis was performed by polyacrylamide gel electrophoresis. Quantitative analysis was performed by densitometry.Results. Total protein content showed a higher protein concentration in porcine valve tissue than in pericardialtissue: 149 ± 22.6 μg/mg dry tissue versus 108 ± 12.7 μg/mg dry tissue (38% increase). In pericardial tissue, four protein bands (17, 16, 15.5, and 13.5 kd) showed decreased concentration when compared with porcine valve tissue, whereas one band (11 kd) showed increased concentration.Conclusions. Significant differences were found in protein content between bovine pericardial and porcine valve tissues. Correlations with clinical findings may lead to a better understanding of the mechanism involved in the process of calcification, particularly the role played by the structure of the tissues.

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. For group I (n = 6), the GPBP strips were fixed on the lung with nonabsorbable suture by thoracotomy. In Group II (n = 6), the resection and fixation of the GPBP strips were performed with an endoscopic linear stapler by thoracotomy. In Group III (n = 6), the resection and fixation of the GPBP strips were performed with a linear stapler by thoracoscopy. The animals were evaluated each day during the first week after surgery and every other day during the study time. At the end of the study all animals were euthanized with an overdose of pentobarbital. Macroscopic and microscopic examinations of the bioprosthesis and lung were evaluated. All animals survived the surgical procedure and study time (8 weeks). In the three groups, macroscopic examination of the bioprosthesis showed good adaptation to the lung tissue. Microscopically, all groups of animals presented good healing, with the presence of fibrotic tissue layer on the GPBP and its periphery as well as in the lung. However, in group I we observed the presence of giant cells in the suture line. GPBP proved to be a useful material for reinforcement of the nonanatomic resection suture line of lung tissue in dogs.

Identification of specific calcium-binding noncollagenous proteins associated with glutaraldehyde-preserved bovine pericardium in the rat subdermal model.

Calcification of glutaraldehyde-preserved bioprosthetic heart valves (BHVs) results in their clinical failure. The mechanism of this pathologic calcification is not well defined. Since serum proteins are known to be taken up in mineralized tissue, we hypothesized that serum proteins derived from several calcium-binding noncollagenous proteins (NCPs) of bone and teeth also may be associated with pathologically mineralized BHVs. Using a rat subdermal model of BHV calcification, glutaraldehyde-preserved bovine pericardium (GPBP) was implanted for 1, 3, 14, and 60 days, and then subjected to an extraction procedure designed to isolate only NCPs tightly bound to the mineral phase. Gel electrophoresis and Coomassie Brilliant Blue staining demonstrated that these proteins became associated with GPBP over time, paralleling reported calcium uptake by the tissue. Stains-All staining demonstrated a marked accumulation of highly acidic, phosphorylated NCPs associated with 60-day GPBP extracts. Some of these proteins were detected in rat serum but were absent from extracts of GPBP incubated in rat serum in vitro. Western blotting with antibodies to three NCPs found in bone and teeth-bone acidic glycoprotein 75 (BAG 75), osteopontin, and SPARC-demonstrated that these NCPs were tightly bound to the mineral phase of calcified GPBP. A fourth NCP, bone sialoprotein II (BSP II) was barely detectable. Thus each identified NCP showed a different pattern of GPBP association relative to mineral deposition, suggesting unique roles for each in pathologic calcification. SPARC increased within 3 days of GPBP implantation but decreased by 2 weeks. BAG 75 and osteopontin uptake was detected in the initial mineral deposits and increased mineralization proceeded. BSP II never increased significantly over the entire-period. Further studies, which should include immunohistochemistry, will be important for delineating the source, location, and function of these three NCPs and for identifying others that also may be involved in this pathological process. Most important, the new insights into the mechanism of pathologic calcification described here present exciting opportunities for novel approaches to BHV calcification prevention.

Thoracoabdominal wall repair with glutaraldehyde-preserved bovine pericardium.

Glutaraldehyde-preserved bovine pericardium (GPBP) is evaluated as a bioprosthesis for the reconstruction of surgical defects in the thoracoabdominal wall. The mechanical properties of bovine pericardium preserved at different concentrations of glutaraldehyde were studied. Samples preserved in 0.5% glutaraldehyde showed a significantly higher tensile strength (11.7 +/- 0.8 N/mm2) than samples preserved in 2.5, 5, or 10% (similar to pericardium preserved in normal saline). The percentage of elongation was significantly lower than samples preserved in 1, 2.5, and 5% glutaraldehyde. GPBP at 0.5% was used to repair experimentally induced defects of the abdominal wall (n = 9), chest wall (n = 6), diaphragm (n = 6), and sternum (n = 7). All animals presented adequate tolerance to the material used and no case of infection or rejection of the material was seen in any of the animals. Finally, 0.5% GPBP was used clinically in a series of 40 patients: postincisional abdominal hernia (n = 30), inguinal hernia (n = 8), diaphragmatic hernia (n = 1), and congenital pelvic defect with prolapse of abdominal organs (n = 1). Surgical use showed that GPBP was a very manageable material and long-term results were good in 37 patients with a mean follow up of 18 months (range 5-35 months). Six patients presented seroma formation (all abdominal hernia patients), three of which eventually developed infection and had the GPBP patch removed at 3, 5, and 7 months postoperatively. The rest of the patients presented good scar formation with adequate resistance at the area of implantation. GPBP is a biological material with sufficient resistance to be used surgically in the repair of thoracoabdominal defects. Ideal concentration of glutaraldehyde to be used in the preparation-preservation of the material is 0.5% since higher concentration negatively affect its tensile rupture strength and elongation.

Pericardial closure after cardiac operations: An animal study to assess currently available materials with particular reference to their suitability for use after coronary artery bypass grafting

An experimental study to assess the performance of currently available pericardial substitutes is described with particular reference to their use after coronary artery bypass grafting. Seventy-two ewes, (six groups of 12 animals) had a 7 x 5 cm portion of the pericardium excised. Each group had either the defect left open, primarily resutured, replaced with coarse Dexon No. 2 mesh (American Cyanamid Co., Danbury, Conn.), replaced with fine Dexon No. 8 mesh, replaced with glutaraldehyde-preserved bovine pericardium, or replaced with polytetrafluoroethylene 0.1 mm surgical membrane. Six animals from each group were assessed at 3 months and the remaining six animals were assessed at 6 months. The open-defect and resutured groups served as control animals. None of the substitutes proved superior to the open-defect group in the prevention of chest wall/lung-to-pericardium adhesions at either 3 or 6 months. The limitations of the animal model in assessing this aspect of substitute performance are discussed. Whereas the bovine pericardium, polytetrafluorethylene, and Dexon No. 8 mesh groups were superior to the resutured group in the prevention of pericardium-to-epithelium adhesions in the area of the patch, this advantage was lost at 6 months when resuturing proved as effective as polytetrafluoroethylene and bovine pericardium. In all groups there was little tendency to produce generalized pericardial adhesions. At 3 months Dexon No. 8 mesh and bovine pericardium produced the least amount of significant epicardial reaction. In two animals in the 3-month polytetrafluoroethylene group and in one animal in the 6-month polytetrafluoroethylene group, a "fibrous peel" was encountered on the inner surface of the patch, which had also become adherent to the epicardium and had obscured the underlying anatomy. At 6 months the open-defect, resutured, and bovine pericardium groups had produced no significant epicardial reaction. In one animal at 6 months the bovine pericardium had become markedly thickened and degenerative. We do not recommend routine closure of the pericardium after coronary artery operations with any of the substitutes investigated in our study.

Retardation of calcification of bovine pericardium used in bioprosthetic heart valves by phosphocitrate and a synthetic analogue

The purpose of this study was to determine if phosphocitrate (PC), a naturally occurring inhibitor of calcification, and its synthetic analogue, N-sulpho-2-amino tricarballylate (SAT), administered either by daily injection or local delivery via Alzet osmotic minipump, could inhibit calcification of glutaraldehyde-preserved bovine pericardium used in bioprosthetic heart valves, subcutaneously implanted in rats. Local drug delivery, but not systemic administration, was effective. PC, administered by Alzet minipump (12 mg.kg −1.day −1), inhibited calcification significantly (tissue calcium = 5 ± 2 μg/mg dry tissue, mean ± SEM), compared with untreated or saline-treated controls (89 ±9 and 49 ± 9 μg/mg, respectively). SAT, administered by the same route at both the same and a higher molar dosage, was less potent (tissue calcium = 26 ± 9 μg/mg and 17 ± 5 μg/mg, respectively). PC and SAT therapy were not associated with adverse effects. We conclude that locally administered PC and SAT can inhibit intrinsic calcification of bovine pericardium, with PC being more potent.

Pharmacologic inhibition of scar contracture of intracardiac prosthetic patches

Significant fibrosis and contracture often cause complications of pericardial and Dacron grafts within the heart. Both continue to be utilized because more suitable materials are unavailable. Newer prosthetic materials and the administration of drugs that might minimize intracardiac fibrosis and contracture after implantation were studied. Measured patches of three prosthetic materials were implanted into the right atrium of 18 dogs: 6 with expanded polytetrafluoroethylene (PTFE or Gore-Tex—W. L. Gore & Associates, Elkton, Md.), 6 with glutaraldehyde-preserved bovine pericardium, and 6 with Dacron patches. The animals were sacrificed after 8 weeks and gross and microscopic pathologic examinations were performed. The patch materials did not intrinsically shrink but all demonstrated marked distortion from the growth of surrounding scar tissue. In a fourth group of eight dogs with intraatrial Dacron patches, four were treated for 8 weeks with oral 3-aminopropionitrile fumarate, and four were not treated. A blinded observed evaluated the adhesions on a scale of 0 = no adhesions or patch distortion, to 4 = dense adhesions with marked distortion of the patches. The untreated dogs had dense adhesions of the lung and pericardium and the patches were encased in scar tissue with marked distortion. The average score was 3.5. The treated dogs had only minimal pleural adhesions and only a thin neointimal covering of the patch with virtually no distortion. The average score was 1.0 ( P = 0.0032). The tensile strength of the healed atriotomies was evaluated with stress testing. The intact atrial wall ruptured at a force of 2.60 ± 0.37 kg/m/sec 2, the untreated atriotomy wound at 2.38 ± 0.18 kg/m/sec 2, and the treated atriotomy wound at 2.60 ± 0.17 kg/m/sec 2. There was no statistically significant difference among these groups. No other side effects of the 3-aminopropionitrile fumarate were noted, with only a single superficial wound infection caused by early postoperative trauma. Pharmacologic inhibition of scar formation minimized distortion and contracture of intracardiac prosthetic patches and decreased adhesions. Though further experimental evaluations are necessary, prolonged low-dose oral administration of β-aminoproprionitrile (BAPN) may be beneficial in preventing complications of prosthetic implants and reoperative cardiac surgery in children.