Month: September 2022

Front Surg. 2022 May 27;9:881433. doi: 10.3389/fsurg.2022.881433. eCollection 2022.

ABSTRACT

BACKGROUND: Autologous pericardium is considered gold standard for various reconstructive surgical procedures in children. However, processed bovine, equine, and porcine pericardial tissue are also widely used. We investigated structural differences and analyzed alterations caused by industrial processing. Additionally human and equine pericardium explants, used during aortic valve reconstruction were analyzed.

METHODS: Pericardial tissues (native, processed and explanted) were gathered and stained with HE and EvG to visualize collagen as well as elastic fibers. Fiber structures were visualized by light and polarization microscopy. Antibody staining against CD 3, CD 20, and CD 68 was performed to identify inflammation.

RESULTS: Native pericardium of different species showed small differences in thickness, with bovine pericardium being the thickest [bovine: 390 μm (± 40.6 μm); porcine: 223 μm (± 30.1 μm); equine: 260 μm (± 28.4 μm)]. Juvenile pericardium was 277 μm (± 26.7 μm). Single collagen bundle diameter displayed variations (~3-20 μm). Parallel collagen fibers were densely packed with small inter-fibrillary space. After industrial tissue processing, loosening of collagen network with inter-fibrillary gapping was observed. Pericardium appeared thicker (mean values ranging from 257-670 μm). Processed tissue showed less birefringence under polarized light. All analyzed tissues showed a small number of elastic fibers. Fibrosis, calcification and inflammatory processes of autologous and equine pericardium were observed in patient explants.

CONCLUSION: None of the analyzed tissues resembled the exact structure of the autologous pericardial explant. Degeneration of pericardium starts during industrial processing, suggesting a potential harm on graft longevity in children. A careful surgical approach prior to the implantation of xenografts is therefore needed.

PMID:35711712 | PMC:PMC9195290 | DOI:10.3389/fsurg.2022.881433

Arthroscopy. 2022 Jun 16:S0749-8063(22)00342-5. doi: 10.1016/j.arthro.2022.06.004. Online ahead of print.

ABSTRACT

PURPOSE: The purpose of this study was to determine whether the addition of decellularized bovine pericardial patch loaded with mesenchymal stromal cells enhanced bone-to-tendon healing and improved the biomechanical strength of large-to-massive rotator cuff tears in a small animal model.

METHODS: Adipose-derived mesenchymal stromal cells (MSCs) from rat inguinal fat were isolated, cultured, and loaded onto decellularized bovine pericardium patches. To simulate large-to-massive tears, rats were managed with free cage activity for 6 weeks after tear creation. A total of 18 rats were randomly allocated to repair-only (control), repair with pericardial patch augmentation (patch), or repair with MSC loaded pericardial patch augmentation (patch-MSC). Each group had 6 rats (one shoulder of each rat was used for histological evaluation and another for biomechanical evaluation). MSCs seeded on the pericardial patches were traced on four shoulders from 2 other rats at 4 weeks after surgery. Histological evaluation for bone-to-tendon healing and biomechanical testing was carried out at 8 weeks after repair.

RESULTS: MSCs tagged with a green fluorescent protein were observed in the repair site 4 weeks after the repair. One shoulder each in the control and patch groups showed complete discontinuity between the bone and tendon. One shoulder in the control group showed attenuation with only a tenuous connection. Fibrocartilage and tidemark formation at the bone-to-tendon interface (P = .002) and collagen fiber density (P = .040) and orientation (P = .003) were better in the patch-MSC group than in the control or patch group. Load-to-failure in the patch-MSC and patch groups was higher than that in the control group (P = .001 and .009, respectively).

CONCLUSION: Decellularized bovine pericardial patches loaded with adipose-derived and cultured mesenchymal stromal cells enhanced healing in terms of both histology and mechanical strength at 8 weeks following rotator cuff repair in a rat model.

CLINICAL RELEVANCE: Large-to-massive rotator tears need a strategy to prevent retear and enhance healing. The addition of decellularized bovine pericardial patch loaded with MSCs can enhance bone-to-tendon healing and improve biomechanical healing of large-to-massive rotator cuff tears following repair.

PMID:35716989 | DOI:10.1016/j.arthro.2022.06.004

J Card Surg. 2022 Oct;37(10):3214-3221. doi: 10.1111/jocs.16773. Epub 2022 Jul 17.

ABSTRACT

BACKGROUND: The transaortic Morrow procedure is the current gold standard for hypertrophic obstructive cardiomyopathy (HOCM) patients who are resistant to maximum drug therapy. It is controversial whether concomitant mitral valve intervention is necessary. Only a few centers apply for concomitant anterior mitral leaflet extension with a bovine or autologous pericardial patch to further decrease systolic anterior motion. Our aim is to assess the primeval outcomes of thoracoscopic transmitral myectomy with anterior mitral leaflet extension (TTM-AMLE) in symptomatic HOCM patients.

METHODS: Between April 2019 and November 2020, 18 consecutive HOCM patients who underwent TTM-AMLE were enrolled in this study. Preoperative, postoperative, and follow-up outcomes were compared and statistically analyzed.

RESULTS: The mean age was (50.17 ± 6.18) years and 10 (55.56%) were males. 18 (100%) patients had mitral regurgitation preoperatively, and they all successfully underwent TTM-AMLE with a median cardiopulmonary bypass and aortic cross-clamp time of 200.0 (150.8, 232.0), and 127.5 (116.0, 149.0) min, respectively. The median length of ICU stay was 2.7 (1.4, 5.2) days. The interventricular septum thickness was significantly reduced (from 18.03 ± 3.02 mm to 11.91 ± 1.66 mm, p < .001). There was no perioperative mortality, perforation of ventricular septum, or conversion to sternotomy observed. During a median follow-up of 18 months (IQR, 5-24 months), 1 (5.56%) patient had severe mitral regurgitation due to patch detachment and received reoperation. Moderate degree of mitral regurgitation and more than 50 mmHg in left ventricular outflow tract gradient were found in 2 (11.11%), and 1 (5.56%) patients, respectively. 1 (5.56%) patient who had second-degree atrioventricular block received permanent pacemaker implantation postoperatively. Overall, the maximum left ventricular outflow tract gradient (88.50 [59.50, 112.75] mmHg vs. 10.50 [7.00, 15.50] mmHg, p = .002), left ventricular outflow tract velocity (4.70 [3.86, 5.33] m/s vs. 1.60 [1.33, 1.95] m/s, p < .001) and the degree of mitral regurgitation (6.99 ± 4.47 cm² vs. 2.22 ± 1.51 cm² , p = .001) were significantly decreased, with a significant reduction in the proportion of systolic anterior motion (94.44% vs. 16.67%, p < .001).

CONCLUSIONS: The TTM-AMLE is a safe and effective surgical approach for selected patients with HOCM. In our series, it provides excellent relief of left ventricular outflow tract obstruction, while significantly eliminating mitral regurgitation. The early outcomes of TTM-AMLE are satisfactory, but further studies and longer follow-ups are awaited.

PMID:35842814 | DOI:10.1111/jocs.16773

Mediastinum. 2022 Sep 25;6:21. doi: 10.21037/med-20-70. eCollection 2022.

ABSTRACT

Major vessels of the mediastinum such as the superior vena cava (SVC) and bilateral innominate veins can occasionally become involved with aggressive tumors or the mediastinum, including non-small cell lung cancer and thymoma. This may result in partial or complete obstruction. With presentation of these tumors symptoms can often be debilitating and would otherwise be treated with palliative therapy. A select population of patients are candidates for tumor resection. The ability to perform an adequate resection will depend on the ability to create a durable reconstruction of the SVC and bilateral innominate veins. Pre-operative and intra-operative considerations will allow for a safe surgery with few complications to the patient. Furthermore, depending on the extent of resection, there are a variety of techniques for reconstruction. These can range from a primary repair of a partial venous wall resection to a complex replacement of both the SVC and one or both innominate veins. Multiple options exist for the use of these conduits, such as polytetrafluoroethylene, homograft, autologous vein, and bovine or porcine pericardium. Depending on the type of conduit used, the post-operative outcomes will differ. In order to perform this operation safely, proper knowledge and experience is required. We review a variety of strategies used to manage these rare but complex scenarios.

PMID:36164357 | PMC:PMC9385873 | DOI:10.21037/med-20-70

ACS Appl Mater Interfaces. 2022 Aug 24;14(33):37301-37315. doi: 10.1021/acsami.2c06865. Epub 2022 Aug 10.

ABSTRACT

Here, we report the design and development of highly stretchable, compliant, and enzymatic-resistant transiently cross-linked decellularized extracellular matrixes (dECMs) (e.g., porcine small intestine submucosa/dSIS, urinary bladder matrix/dUBM, bovine pericardium/dBP, bovine dermis/dBD, and human dermis/dHD). Specifically, these dECMs were modified with long aliphatic chains (C9, C14, and C18). Upon modification, dECMs became significantly resistant to enzymatic degradation for extended periods, showed increased water contact angle (>20%-90%), and stretched >200% than their control counterparts. Modified dECMs are compliant, undergoing 100% elongation at only 0.3-0.5 MPa of applied tensile stress (∼10%-25% of their control counterparts), similar to the control bladder tissue. Furthermore, modified dECMs remain structurally stable at the physiological temperature with increased storage and loss modulus values but decreased tan δ values compared to their control counterparts. Although modification reduces cell adhesion, the gene expressions in polarized macrophages remain unchanged (e.g., TGFβ, CD163, and CD86), except for the modified bovine pericardium (dBP) where a significant decrease in TNFα gene expression is observed. When implanted in the rat subcutaneous model, modified dECMs degraded relatively slowly and did not cause significant fibrotic tissue formation. The numbers of pro-regenerative macrophages increased to several folds in a later time point of evaluation. Modified dECM also supported the bladder wall regeneration with formations of the urothelium, lamina propria, blood vessels, and muscle bundles and reduced the occurrence of calculi formation by 50% in a rat bladder augmentation model. We anticipate that the enhanced stretchability, compliance, and physiological stability of dECMs indicate their suitability for urologic tissue regeneration.

PMID:35948054 | DOI:10.1021/acsami.2c06865

Front Bioeng Biotechnol. 2022 Jul 12;10:909771. doi: 10.3389/fbioe.2022.909771. eCollection 2022.

ABSTRACT

More than 200,000 patients with aortic diseases worldwide undergo surgical valve replacement each year, and transcatheter heart valves (THV) have been more widely used than ever before. However, THV made by the glutaraldehyde (Glut) crosslinking method has the disadvantage of being prone to calcification, which significantly reduces the durability of biomaterials. In this study, we applied a novel crosslinking method using ribose in THV for the first time, which can decrease calcification and increase the stability of the extracellular matrix (ECM). We incubated the bovine pericardium (BP) in ribose solution at 37°C by shaking for 12 days and confirmed that the structure of the BP was more compact than that of the Glut group. Moreover, the ribose method remarkably enhanced the biomechanical properties and provided reliable resistance to enzymatic degradation and satisfactory cellular compatibility in THV. When the BP was implanted subcutaneously in vivo, we demonstrated that ECM components were preserved more completely, especially in elastin, and the immune-inflammatory response was more moderate than that in the Glut treatment group. Finally, the ribose-cross-linked materials showed better anti-calcification potential and improved durability of THV than Glut-cross-linked materials.

PMID:35903798 | PMC:PMC9315440 | DOI:10.3389/fbioe.2022.909771

Polymers (Basel). 2022 May 26;14(11):2156. doi: 10.3390/polym14112156.

ABSTRACT

(1) Background: Hemocompatibility is a critical challenge for tissue-derived biomaterial when directly contacting the bloodstream. In addition to surface modification with heparin, endothelialization of the grafted material is suggested to improve long-term clinical efficacy. This study aimed to evaluate the ability to endothelialize in vitro of heparinized bovine pericardial scaffolds. (2) Methods: bovine pericardial scaffolds were fabricated and heparinized using a layer-by-layer assembly technique. The heparinized scaffolds were characterized for heparin content, surface morphology, and blood compatibility. Liquid extraction of the samples was prepared for cytotoxicity testing on human endothelial cells. The in-vitro endothelialization was determined via human endothelial cell attachment and proliferation on the scaffold. (3) Results: The heparinized bovine pericardial scaffold exhibited a heparin coating within its microfiber network. The scaffold surface immobilized with heparin performed good anti-thrombosis and prevented platelet adherence. The proper cytotoxicity impact was observed for a freshly used heparinized sample. After 24 h washing in PBS 1X, the cell compatibility of the heparinized scaffolds was improved. In-vitro examination results exhibited human endothelial cell attachment and proliferation for 7 days of culture. (4) Conclusions: Our in-vitro analysis provided evidence for the scaffold’s ability to support endothelialization, which benefits long-term thromboresistance.

PMID:35683829 | PMC:PMC9182580 | DOI:10.3390/polym14112156