TREATMENT OF AORTO-ILIAC AND INFRA-INGUINAL VASCULAR INFECTIONS WITH A PREFABRICATED BOVINE PERICARDIAL GRAFT.

OBJECTIVE: The use of biological grafts provides acceptable mid- and long-term results in native or prosthetic vascular infections. Several reports describe the successful use of bovine pericardium in case of vascular infections, mainly as a large patch to be sutured as a tubular graft. Recently, a novel prefabricated bovine pericardium graft (Biointegral Surgical No-React® Inc, Mississauga, ON, Canada) has been introduced in clinical practice with promising results. In this study, we report our preliminary experience utilizing Biointegral Surgical graft in case of native and or prosthetic aorto-iliac and infra-inguinal infection. METHODS: We retrospectively analyzed data from 20 patients with native or prosthetic aorto-iliac and infra-inguinal infection who underwent in situ reconstruction with a Biointegral Surgical No-React bovine pericardium prosthesis between October 2020 and February 2023 at the Vascular Surgery Unit of the Fondazione Policlinico Universitario Gemelli - IRCCS in Rome, Italy. All patients followed a standardized protocol including postoperative anticoagulation and long-term intravenous antibiotics. RESULTS: The indication for surgery was: mycotic aortic aneurysm in four patients (20%), graft infection after abdominal aortic repair in 11 patients (55%), peripheral graft infection in five patients (25%). Complete excision of the infected aorta or prosthetic graft, surgical debridement and in situ reconstruction were performed in all patients. Hospital mortality rate was 5% (n=1) and graft-related mortality of 0%. During follow-up (median 13 months, range 6-34 months), reinfection was 5.2% and primary graft patency 94.7%. CONCLUSIONS: The use of prefabricated bovine pericardial grafts represent a promising option for the treatment of native and prosthetic aorto-iliac and infra-inguinal infections. The application of this biological graft with a standardized post-operative protocol has been associated with a satisfactory patency and reinfection rate without increased bleeding complications.

Physician-made pericardium stent graft as a potential endovascular alternative for infectious aortic disease - an ex-vivo proof-of-concept study.

PURPOSE.: The treatment of infectious aortic disease is still challenging with open surgical debridement and reconstruction using biological, preferably autologous material, being the treatment of choice. However, these procedures are associated with high morbidity and mortality. Endovascular therapy is often considered a bridging method only, since the biologically inactive fabric of the covered stent grafts usually cannot be treated sufficiently with anti-infective agents in the event of a (obligate) consecutive secondary graft infection. This study aims to prove the feasibility of a physician-made pericardium stent graft ex-vivo. TECHNIQUE.: A state-of-the-art TEVAR was modified by separating the fabric from the z-stents and suturing a hand-sewn bovine pericardium tube to the bare metal. Feasibility of preparation, re-sheathing, and delivery is demonstrated in an ex-vivo model. CONCLUSION.: This first xenogeneic stent graft could be manufactured and deployed successfully. In the future this may provide a bridging alternative for high-risk patients with infected native aortic aneurysm or aortic fistulas, eventually followed by surgical or thoracoscopic/laparoscopic debridement. Further studies on simulators or animal models are needed to test the technique and investigate its long-term durability. Additionally, this study prompts reflection on whether materials currently used should be further developed to prevent graft infections.

Revision Surgery is Possible in Patients With Previous Bovine Pericardium Inferior Vena Cava Reconstruction: A Case Series and Review of Literature.

There is a paucity of research investigating revision surgery for patients with previous inferior vena cava (IVC) reconstruction using bovine pericardium (BP). To the best of our knowledge, no reports of redo procedures have been published in the medical literature. We describe two cases of redo surgery in patients with previous IVC reconstructions using BP following disease recurrence. The first case underwent resection of the BP graft with a second IVC reconstruction using BP, the second case underwent resection of the BP graft without reconstruction due to extensive thromboses. Neither case experienced perioperative complication or morbidity following their redo procedure, and previous IVC reconstruction with BP did not present significant intraoperative technical challenges. One case showed evidence of endothelialisation of the excised BP graft, however, it was not possible to definitively conclude if endothelialisation was present in the second case. Overall, these cases demonstrate that previous IVC reconstruction using BP should not be considered an absolute contraindication for redo surgery in the context of disease recurrence.

The Measurement of Bovine Pericardium Density and Its Implications on Leaflet Stress Distribution in Bioprosthetic Heart Valves.

PURPOSE: Bioprosthetic Heart Valves (BHVs) are widely used in clinical practice, showing promising outcomes. Computational modeling offers a valuable tool for quantitatively characterizing BHVs. To ensure the accuracy of computational models, it is crucial to consider precise leaflet properties, including mechanical properties and density. Bovine pericardium (BP) serves as a common material for BHV leaflets. Previous computational studies often assume BP density to approximate that of water or blood. Given that BP leaflets undergo various treatments, such as tissue fixation and anti-calcification, this study aims to measure the density of BP used in BHVs and assess its impact on leaflet stress distribution. METHODS: Eight square BP samples were laser cut from Edwards BP patches and their density was determined. Specimen weight was measured using an A&D Analytical Balance, while volume was assessed through high-resolution imaging. Additionally, finite element models resembling a BHV, like the Carpentier-Edwards PERIMOUNT Magna, were constructed in ABAQUS. RESULTS: The average density of the BP samples was found to be 1,410 kg/m3. During the acceleration phase of a cardiac cycle, the maximum stress reached 1.89 MPa for a density of 1,410 kg/m3 and 2.47 MPa for a density of 1,000 kg/m3 (a 30.7% difference). In the deceleration phase, the maximum stress reached 713 kPa and 669 kPa, respectively. CONCLUSION: Leaflet stress distribution and motion in BHVs are influenced by density variations. Establishing an accurate density value for BHV leaflets is imperative for enhancing the computational models, which can ultimately contribute to improved BHV design and outcomes.

Implant-Based Breast Reconstruction with Bovine Pericardium: Our Approach Using Tutopatch® and Review of Literature.

OBJECTIVES: To describe the usage and advantages of bovine pericardium mesh (Tutopatch®) in breast reconstruction and to compare different mesh materials used in immediate breast reconstruction. METHODS: Our study involved a single-center, retrospective analysis of 103 patients (comprising 114 breasts) who underwent immediate implant-based breast reconstruction using bovine pericardium bovine matrix. The procedures were performed by the same surgical team between April 2018 and May 2023. RESULTS: The rates of early and late complications were examined after a median follow-up period of 30.2 ± 5.5 months. The results revealed that the rates of early complications stood at 9.7%, while late complications were observed in 14.5% of the cases. The most common late complication was seroma formation (7.7%) which six were resolved without any surgical intervention. CONCLUSION: Tutopatch® can be used as an extension of the muscle to cover the prosthesis. It forms an extra layer over the silicone implant that helps to decrease the complications as capsular contracture and implant exposure. It also represents a significant 85 % reduction in cost when compared to a similar-sized mesh materials. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Femorotibial Bypass Sutured on Bovine Pericardium Patch of the Femoral Artery for Bypass Inflow: A Case Report.

A 72-year-old man presented with intermittent claudication and a foot ulcer. Computed tomography revealed severe calcification and occlusion of the left femoral artery and calcification and stenosis from the superficial femoral artery to the popliteal artery. Thromboendarterectomy (TEA) and anterior reconstruction of the femoral artery with a bovine pericardium patch were performed. We sutured the great saphenous vein on the bovine pericardium patch for bypass inflow after creating an anastomosis hole with a puncher and performed an in situ femorotibial bypass. This technique helped us achieve a smooth and clean anastomosis. In situ vein graft anastomosis might be difficult on severely atherosclerotic femoral artery after TEA and difficult anastomosis increases the risk of bypass occlusion. Anastomosis on the bovine pericardium patch for bypass inflow might ensure smooth and clean anastomosis in patients with severe atherosclerosis of the femoral artery.

An In Vitro Study of Chitosan-Coated Bovine Pericardium as a Dural Substitute Candidate.

Defects in the dura matter can be caused by head injury, and many cases require neurosurgeons to use artificial dura matter. Bovine pericardium is an option due to its abundant availability, adjustable size and characteristics, and because it has more collagen than porcine or equine pericardia. Nevertheless, the drawback of bovine pericardium is that it has a higher inflammatory effect than other synthetic dura matters. Chitosan has been shown to have a strong anti-inflammatory effect and has good tensile strength; thus, the idea was formulated to use chitosan as a coating for bovine pericardium. This study used decellularized bovine pericardial membranes with 0.5% sodium dodecyl sulphate and coatings containing chitosan at concentrations of 0.25%, 0.5%, 0.75%, and 1%. An FTIR test showed the presence of a C=N functional group as a bovine pericardium-chitosan bond. Morphological tests of the 0.25% and 0.5% chitosan concentrations showed standard pore sizes. The highest tensile strength percentage was shown by the membrane with a chitosan concentration of 1%. The highest degradation rate of the membrane was observed on the 7th and 14th days for 0.75% and 1% concentrations, and the lowest swelling ratio was observed for the 0.25% concentration. The highest level of cell viability was found for 0.75% chitosan. The bovine pericardium membrane with a 0.75% concentration chitosan coating was considered the optimal sample for use as artificial dura matter.

CardioCel® for repair of congenital heart defects: nationwide results of over 1000 implants.

OBJECTIVES: To assess the mid-term performance of CardioCel for the repair of congenital heart defects. METHODS: Data were retrospectively collected from databases and hospital records in 3 congenital cardiac surgery centres in Australia. Kaplan-Meier curves and log-rank tests were used to test for associations between patient age, gender, patch type and site of implantation. Multivariable Cox regression was used to test whether any specific implantation site was associated with reintervention risk, after adjusting for age group, gender and patch type. RESULTS: A total of 1184 CardioCel patches were implanted in 752 patients under the age of 18 years. Median age at implant was 12 months [interquartile range (IQR) 3.6-84]. Median follow-up was 2.1 years (IQR 0.6-4.6). Probability of freedom from CardioCel-related reintervention was 93% [95% confidence interval (CI) 91-95] at 1 year, 91% (95% CI 88-93) at 3 years and 88% (95% CI 85-91) at 5 years, respectively. On multivariable regression analysis, aortic valve repair had a higher incidence of reintervention [hazard ratio (HR) = 7.15, P = 0.008] compared to other sites. The probability of reintervention was higher in neonates (HR = 6.71, P = 0.0007), especially when used for augmentation of the pulmonary arteries (HR = 14.38, P = 0.029), as compared to other age groups. CONCLUSIONS: CardioCel can be used for the repair of a variety of congenital heart defects. In our study, in patients receiving a CardioCel implant, reinterventions were higher when CardioCel was used to augment the pulmonary arteries in neonates and for aortic valve repair as compared to other sites.

Monomeric glutaraldehyde fixation and amino acid detoxification of decellularized bovine pericardium for production of biocompatible tissue with tissue-guided regenerative potential.

The effect of monomeric glutaraldehyde fixation and amino acid detoxification on biocompatibility and tissue-guided regenerative potential of decellularized bovine pericardium was evaluated. The degree of cross-linking, porosity, enzymatic degradation, alpha-galactosyl content, the efficacy of detoxification, and cytotoxicity towards human epithelial cells were assessed. Tissue was subcutaneously implanted for eight weeks in male juvenile Sprague-Dawley rats, and mechanical properties, host cell infiltration, and calcification were evaluated. Three groups were compared i) decellularized tissue, ii) decellularized, monomeric glutaraldehyde fixed and amino acid detoxified tissue, and iii) commercial glutaraldehyde fixed non-decellularized tissue (Glycar®) (n = 6 rats per group). The fixation process gave a high degree of cross-linking (>85%), and was resistant to enzymatic degradation, with no significant effect on porosity. The detoxification process was effective, and the tissue was not toxic to mammalian cells in vitro. Tissue from both decellularized groups had significantly higher (p < 0.05) porosity and host cell infiltration in vivo. The process mitigated calcification. A non-significant decrease in the alpha-galactosyl content was observed, which increased when including the alpha-galactosidase enzyme. Mechanical properties were maintained. The fixation and detoxification process adequately removes free aldehyde groups and reduces toxicity, preventing enzymatic degradation and allowing for host cell infiltration while mitigating calcification and retaining the mechanical properties of the tissue. This process can be considered for processing decellularized bovine pericardium with tissue-guided regeneration potential for use in cardiovascular bioprostheses; however, methods of further reducing antigenicity, such as the use of enzymes, should be investigated.

Biostimulation effect of platelet-rich fibrin augmented with decellularized bovine pericardium on full-thickness cutaneous wound healing in Donkeys (Equus asinus).

AIM: The current research aimed to evaluate the potential effect of adding platelet-rich fibrin (PRF) to the decellularized bovine pericardium (DBP) on the distal limb of donkeys' full-thickness cutaneous wounds healing (Equus asinus). MATERIALS AND METHODS: Healthy male donkeys (n = 12) were used in this study. Under general anesthesia, 6 cm2 full-thickness incisions were made on the middle dorsolateral surface of both forelimbs' metacarpi. The left forelimbs were control wounds, while the right wounds were treated with PRF/DBP. Control wounds were bandaged with a standard dressing after saline irrigation and were evaluated at days 4, 7, 10, 13, 16, 19, 22, 25, and 28 post-wounding. PRF/DBP-treated wounds were dressed with a combination of PRF/DBP at the first, second, and third weeks post-wounding. Clinical and histopathological examinations of the wounds were performed to assess the healing process. Additionally, the immunohistochemical evaluation and gene expression profiles of myofibroblastic and angiogenic genes (transforming growth factor-ß1, vascular endothelial growth factor-A, fibroblast growth factor 7 (FGF-7), and collagen type 3α1) were analyzed. RESULTS: PRF/DBP wounds had a significantly faster healing process (61.3 ± 2.6 days) than control wounds (90.3 ± 1.4 days) (p < 0.05). The immunohistochemical examination and gene expression profile revealed significant enrichment in PRF/DBP wounds compared to control wounds. CONCLUSION: PRF/DBP dressing can be considered a natural and cost-effective biomaterial for enhancing the recovery of donkeys' distal limb injuries.

In vitro evaluation of crosslinked bovine pericardium as potential scaffold for the oral cavity.

BACKGROUND: Bovine pericardium (BP) is a scaffold widely used in soft tissues regeneration; however, its calcification in contact with glutaraldehyde, represent an opportunity for its application in hard tissues, such as bone in the oral cavity. OBJECTIVE: To develop and to characterize decellularized and glutaraldehyde-crosslinked bovine pericardium (GC-BP) as a potential scaffold for guided bone regeneration GBR. METHODS: BP samples from healthy animals of the bovine zebu breed were decellularized and crosslinked by digestion with detergents and glutaraldehyde respectively. The resulting cell-free scaffold was physical, chemical, mechanical, and biologically characterized thought hematoxylin and eosin staining, DNA quantification, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), uniaxial tensile test, cell viability and live and dead assay in cultures of dental pulp stem cells (DPSCs). RESULTS: The decellularization and crosslinking of BP appeared to induce conformational changes of the CLG molecules, which led to lower mechanical properties at the GC-BP scaffold, at the same time that promoted cell adhesion and viability of DPSCs. CONCLUSION: This study suggests that the decellularized and GC-BP is a scaffold with the potential to be used promoting DPSCs recruitment, which has a great impact on the dental area.

Comparison of Bovine- and Porcine-Derived Decellularized Biomaterials: Promising Platforms for Tissue Engineering Applications.

Animal-derived xenogeneic biomaterials utilized in different surgeries are promising for various applications in tissue engineering. However, tissue decellularization is necessary to attain a bioactive extracellular matrix (ECM) that can be safely transplanted. The main objective of the present study is to assess the structural integrity, biocompatibility, and potential use of various acellular biomaterials for tissue engineering applications. Hence, a bovine pericardium (BP), porcine pericardium (PP), and porcine tunica vaginalis (PTV) were decellularized using a Trypsin, Triton X (TX), and sodium dodecyl sulfate (SDS) (Trypsin + TX + SDS) protocol. The results reveal effective elimination of the cellular antigens with preservation of the ECM integrity confirmed via staining and electron microscopy. The elasticity of the decellularized PP (DPP) was markedly (p < 0.0001) increased. The tensile strength of DBP, and DPP was not affected after decellularization. All decellularized tissues were biocompatible with persistent growth of the adipose stem cells over 30 days. The staining confirmed cell adherence either to the peripheries of the materials or within their matrices. Moreover, the in vivo investigation confirmed the biocompatibility and degradability of the decellularized scaffolds. Conclusively, Trypsin + TX + SDS is a successful new protocol for tissue decellularization. Moreover, decellularized pericardia and tunica vaginalis are promising scaffolds for the engineering of different tissues with higher potential for the use of DPP in cardiovascular applications and DBP and DPTV in the reconstruction of higher-stress-bearing abdominal walls.

The clinical effectiveness of staple line reinforcement with different matrix used in surgery.

Staplers are widely used in clinics; however, complications such as bleeding and leakage remain a challenge for surgeons. To tackle this issue, buttress materials are recommended to reinforce the staple line. This Review provides a systematic summary of the characteristics and applications of the buttress materials. First, the physical and chemical properties of synthetic polymer materials and extracellular matrix used for the buttress materials are introduced, as well as their pros and cons in clinical applications. Second, we review the clinical effects of reinforcement mesh in pneumonectomy, sleeve gastrectomy, pancreatectomy, and colorectal resection. Based on the analysis of numerous research data, we believe that buttress materials play a crucial role in increasing staple line strength and reducing the probability of complications, such as bleeding and leakage. However, considering the requirements of bioactivity, degradability, and biosafety, non-crosslinked small intestinal submucosa (SIS) matrix material is the preferred candidate. It has high research and application value, but further studies are required to confirm this. The aim of this Review is to provide comprehensive guidance on the selection of materials for staple line reinforcement.

A mid- and long-team follow-up study of the application of single-valved bovine pericardium patches in right ventricular outflow tract reconstruction.

Background: Pulmonary regurgitation following right ventricular outflow tract (RVOT) reconstruction may cause right heart dysfunction and even right heart failure. Installation of a single valve at this time point can effectively reduce pulmonary regurgitation, thereby protecting right heart function. Here, we analyzed the outcomes and mid- and long-term follow-up data of patients undergoing single-valved bovine pericardium patch (svBPP) placement for reconstruction and explored the effectiveness and gaps of svBPP in preventing right heart failure. Methods: A retrospective analysis was performed on patients undergoing RVOT reconstruction using BalMonocTM svBPP from October 2010 to August 2020. The follow up procedures included outpatient visits and collection of outcomes. The cardiac ultrasound-related indicators during the follow-up visits included ejection fraction (EF), right ventricular end-diastolic diameter (EDD), pulmonary regurgitation, and pulmonary artery stenosis. The survival rates and reoperation-free rate were analyzed by Kaplan-Meier method. Results: Patients includes tetralogy of Fallot, pulmonary atresia and other complex congenital heart disease. A total of 5 patients (5.7%) died during the perioperative period. Early complications included pleural effusion, cardiac insufficiency, respiratory insufficiency, chylothorax, and atelectasis, all of which were cured. After discharge, 83 patients (94.3%) were effectively followed up. During follow-up, 1 patient died and 1 patient underwent reoperation. The 1-, 5-, and 10-year survival rates were 98.8%, 98.8%, and 98.8%, respectively, and the reintervention-free rates for the same intervals were 98.8%, 98.8%, and 98.8%, respectively. The last follow-up ultrasound revealed severe pulmonary stenosis in 0 cases, moderate stenosis in 2 cases, mild stenosis in 7 cases, and no stenosis in 73 cases. Pulmonary regurgitation was not found in 12 patients; however, there were 2 cases of severe pulmonary regurgitation, 20 cases of moderate pulmonary regurgitation, and 48 cases of mild pulmonary regurgitation. Conclusions: As shown in the mid- and long-term follow-up studies, BalMonocTM svBPP has good performance in RVOT reconstruction. It can effectively eliminate or reduce pulmonary valve regurgitation and protect right heart function. Both réparation à l'Etage ventriculaire (REV) and the modified Barbero-Marcial procedure can bring growth potential and reduce reoperation rate.

Covalently Grafted Peptides to Decellularized Pericardium: Modulation of Surface Density.

The covalent functionalization of synthetic peptides allows the modification of different biomaterials (metallic, polymeric, and ceramic), which are enriched with biologically active sequences to guide cell behavior. Recently, this strategy has also been applied to decellularized biological matrices. In this study, the covalent anchorage of a synthetic peptide (REDV) to a pericardial matrix decellularized via Schiff base is realized starting from concentrated peptide solutions (10-4 M and 10-3 M). The use of a labeled peptide demonstrated that as the concentration of the working solution increased, the surface density of the anchored peptide increased as well. These data are essential to pinpointing the concentration window in which the peptide promotes the desired cellular activity. The matrices were extensively characterized by Water Contact Angle (WCA) analysis, Differential Scanning Calorimetry (DSC) analysis, geometric feature evaluation, biomechanical tests, and preliminary in vitro bioassays.

Performance of CardioCel in Cardiac Surgery: A Systematic Review.

A systematic review was performed for evaluation of the performance of CardioCel® in cardiac surgery. The review included all studies published from January 2013 to December 2020. We conclude that CardioCel is a strong, flexible tissue substitute with good handling characteristics and a low incidence of thrombosis, aneurysm formation, infection, or structural degeneration. It can be used for a variety of intracardiac and extracardiac repairs of congenital heart defects in all age groups with good durability at mid-term follow-up. However, the use of CardioCel in certain positions requires caution. Information on the long-term performance of CardioCel is lacking.

Editor's Choice - Nationwide Outcome Analysis of Primary Carotid Endarterectomy in Symptomatic Patients Depending on Closure Technique and Patch Type.

OBJECTIVE: Current European guidelines recommend both eversion carotid endarterectomy (CEA) and conventional CEA with routine patch closure, rather than routine primary closure. Polyester and polytetrafluoroethylene (PTFE) have been used as patch material for a long time. More recently, bovine pericardium has been used; however, there are few studies comparing long term results between bovine pericardium and other patch types. The aim of this study was to investigate the short and long term results after CEA depending on surgical technique and patch material. METHODS: A registry based study on all primary CEAs (n = 9 205) performed for symptomatic carotid artery stenosis in Sweden from July 2008 to December 2019, cross linked with data from the Swedish stroke registry, Riksstroke, and chart review for evaluation of any events occurring during follow up. The primary endpoint was ipsilateral stroke < 30 days. Secondary endpoints included re-operations due to neck haematoma and < 30 day ipsilateral stroke, > 30 day ipsilateral stroke, all stroke > 30 days, and all cause mortality. RESULTS: 2 495 patients underwent eversion CEA and 6 710 conventional CEA for symptomatic carotid stenosis. The most commonly used patch material was Dacron (n = 3 921), followed by PTFE (n = 588) and bovine pericardium (n = 413). A total of 1 788 patients underwent conventional CEA with primary closure. Two hundred and seventy-three patients (3.0%) had a stroke < 30 days. Primary closure was associated with an increased risk of ipsilateral stroke and stroke or death <30 days: odds ratio 1.7 (95% confidence interval [CI] 1.2 - 2.4, p = .002); and 1.5 (95% CI 1.2 - 2.0), respectively. During follow up (median 4.2 years), 592 patients had any form of stroke and 1 492 died. There was no significant difference in long term risk of ipsilateral stroke, all stroke, or death depending on surgical technique or patch material. CONCLUSION: There was an increased risk of ipsilateral stroke < 30 days in patients operated on with primary closure compared with eversion CEA and patch angioplasty. There was no difference between primary closure, different patch types, or eversion after the peri-operative phase.

Mechanical reinforcement of amniotic membranes for vesicovaginal fistula repair.

INTRODUCTION: Amniotic membranes (AM) have shown its great potential in reconstructive surgery due to their regenerative capacity. However, AM is regarded to be relatively weak when applied for load-bearing purposes. This study aims to produce an AM-based scaffold that can withstand the mechanical loads applied in vesicovaginal fistula repair. Different strategies are investigated to improve the mechanical characteristics of AM. METHODS: Single and multilayered AM, and composite constructs of AM with electrospun poly-4-hydroxybutyrate (P4HB) or bovine pericardial tissue combined with the use of fibrin glue, were mechanically tested in this study. Suture retention strength and mechanical characteristics (tensile stress, elongation, tangent modulus and maximum load) were assessed by uniaxial testing. The effect of degradation of the composite constructs on the mechanical characteristics was determined by uniaxial testing after 4 and 8 weeks. RESULTS: Single and multilayered AM could not provide the mechanical requirements needed for surgical implantation (>2N load). AM was combined successfully with electrospun P4HB and bovine pericardium with the use of fibrin glue and were able to exceed the 2N load. CONCLUSION: The composite constructs with AM showed sufficient mechanical characteristics for surgical implantation. Electrospun P4HB combined with AM seemed the most promising candidate since the mechanical characteristics of P4HB can be further modified to meet the requirements of the application site and the degradation of the P4HB allows a gradual transfer of load. Eventhough the scaffold is intended for fistula repair, it can potentially be applied in surgical reconstruction of other hollow organs by modifying the mechanical characteristics.

Bovine pericardium leaflet damage during transcatheter aortic valve crimping: a study of the mechanisms.

Leaflet damage has been documented to occur while deploying a transcatheter aortic valve (TAV) due to mechanical loads during the crimping procedures. In this study, the impact of compressive stress on folded leaflets was measured to investigate the mechanism of traumatic leaflet tissue damage. Numerical simulation of TAV crimping procedure was adapted to calculate stress magnitude and distribution of leaflets. A 20 mm balloon expanding short stent TAV with 0.25 mm thickness leaflets was used in the simulation. Then the calculated stresses were applied on leaflet material (bovine pericardium) samples by loading experiments. Mechanical properties evaluation combined with histological and microscopy observation were used to investigate the tissue damage. The elastic modulus and the tensile strength of the tissue began to decrease significantly at 2 MPa stress and 2.5 MPa stress, respectively. No significant differences were observed at 0-1.5 MPa stress. When the TAV was crimped to 14 Fr and 12 Fr, the 2 MPa greater areas on leaflets increased from 18.17% to 76.96%. 2 MPa compressive stress might be the threshold value for leaflet damage. The TAV crimping size should be paid attention to avoid the compressive stress higher than 2 MPa.

Acellular bovine pericardium as a biological dressing for treatment of cutaneous wounds of the distal limb in donkeys (Equus Asinus).

This research was performed to determine the impact of repeated topical dressing with acellular bovine pericardium (ABP) on healing distal limb wounds in donkeys. Twelve male clinically healthy donkeys were subjected to general anesthesia, and full-thickness wounds of six cm2 (2 × 3 cm) were created on the middle dorsolateral surface of the metacarpi. Two defects were made on each donkey's forelimbs; the right limb was considered a control wound, and the left one was considered a treated wound. Moreover, the control wounds were irrigated with saline every three days postoperatively and bandaged with a standard dressing. The treated wounds were covered with ABP dressings. The ABP dressing was reapplied thrice at 7-, 14- and 21-days post-wound induction. In addition, the wound healing process was monitored clinically, histopathologically, and immunohistochemically of tissue as growth factor-ß1, epidermal growth factor receptor, and vascular endothelial growth factor. Besides, the gene expression profile of angiogenic and myofibroblastic genes was applied as vascular endothelial growth factor-A, collagen type 3α1, fibroblast growth factor 7, and the transforming growth factor-ß1.The results revealed that the wounds treated with ABP healed more quickly than the control wounds. Additionally, the mean days required for healing were significantly shorter in the ABP-treated wounds (p < 0.05; 69.5 ± 1.6) compared to control wounds (86.3 ± 3). Furthermore, immunohistochemical and gene expression analyses were significantly improved in ABP wounds than in control wounds. In conclusion, ABP is considered a natural biomaterial and promotes the healing of distal limb wounds in donkeys if applied weekly during the first three-week post-wound induction.