Category: General

J Cardiovasc Dev Dis. 2022 Aug 22;9(8):282. doi: 10.3390/jcdd9080282.

ABSTRACT

Aortic stenosis is the most common valve disease requiring surgery or percutaneous treatment. Since the first-in-man implantation in 2002 we have witnessed incredible progress in transcatheter aortic valve implantation (TAVI). In this article, we review the technical aspects of TAVI development with a look at the future. Durability, low thrombogenicity, good hydrodynamics, biocompatibility, low catheter profile, and deployment stability are the attributes of an ideal TAVI device. Two main design types exist-balloon-expandable and self-expanding prostheses. Balloon-expandable prostheses use a cobalt-chromium alloy frame providing high radial strength and radiopacity, while the self-expanding prostheses use a nickel-titanium (Nitinol) alloy frame, which expands to its original shape once unsheathed and heated to the body temperature. The valve is sewn onto the frame and consists of the porcine or bovine pericardium, which is specially treated to prevent calcinations and prolong durability. The lower part of the frame can be covered by polyethylene terephthalate fabric or a pericardial skirt, providing better sealing between the frame and aortic annulus. The main future challenges lie in achieving lower rates of paravalvular leaks and new pacemaker implantations following the procedure, lower delivery system profiles, more precise positioning, longer durability, and a good hemodynamic profile. Patient-specific design and the use of autologous tissue might solve these issues.

PMID:36005446 | PMC:PMC9409777 | DOI:10.3390/jcdd9080282

Biomimetics (Basel). 2022 Aug 1;7(3):104. doi: 10.3390/biomimetics7030104.

ABSTRACT

Human and animal pericardia are among the most widely exploited materials suitable to repair damaged tissues in the cardiovascular surgery context. Autologous, xenogeneic (chemically treated) and homologous pericardia are largely utilized, but they do exhibit some crucial drawbacks. Any tissue treated with glutaraldehyde is known to be prone to calcification in vivo, lacks regeneration potential, has limited durability, and can result in cytotoxicity. Moreover, autologous tissues have limited availability. Decellularized biological tissues represent a promising alternative: decellularization removes cellular and nuclear components from native tissues and makes them suitable for repopulation by autologous cells upon implantation into the body. The present work aims to assess the effects of a new detergent, i.e., Tergitol, for decellularizing bovine and porcine pericardia. The decellularization procedure successfully removed cells, while preserving the histoarchitecture of the extracellular matrix. No cytotoxic effect was observed. Therefore, decellularized pericardia showed potential to be used as scaffold for cardiovascular tissue regeneration.

PMID:35997424 | PMC:PMC9397045 | DOI:10.3390/biomimetics7030104

Comput Methods Biomech Biomed Engin. 2022 Aug 11:1-10. doi: 10.1080/10255842.2022.2110378. Online ahead of print.

ABSTRACT

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.

PMID:35951008 | DOI:10.1080/10255842.2022.2110378

Front Bioeng Biotechnol. 2022 Sep 9;10:1008664. doi: 10.3389/fbioe.2022.1008664. eCollection 2022.

ABSTRACT

The bioprosthetic heart valves (BHVs) are the best option for the treatment of valvular heart disease. Glutaraldehyde (Glut) is commonly used as the golden standard reagent for the crosslinking of BHVs. However, the obvious defects of Glut, including residual aldehyde toxicity, degradation and calcification, increase the probability of valve failure in vivo and motivated the exploration of alternatives. Thus, the aim of this study is to develop a non-glutaraldehyde hybrid cross-linking method composed of Neomycin Trisulfate, Polyethylene glycol diglycidyl ether and Tannic acid as a substitute for Glut, which was proven to reduce calcification, degradation, inflammation of the biomaterial. Evaluations of the crosslinked bovine pericardial included histological and ultrastructural characterization, biomechanical performance, biocompatibility and structural stability test, and in vivo anti-inflammation and anti-calcification assay by subcutaneous implantation in juvenile Sprague Dawley rats. The results revealed that the hybrid crosslinked bovine pericardial were superior to Glut crosslinked biomaterial in terms of better hydrophilicity, thermodynamics stability, hemocompatibility and cytocompatibility, higher Young’s Modulus, better stability and resistance to enzymatic hydrolysis, and lower inflammation, degradation and calcification levels in subcutaneous implants. Considering all above performances, it indicates that the hybrid cross-linking method is appropriate to replace Glut as the method for BHV preparation, and particularly this hybrid crosslinked biomaterials may be a promising candidate for next-generation BHVs.

PMID:36159659 | PMC:PMC9500414 | DOI:10.3389/fbioe.2022.1008664

Curr Probl Cardiol. 2022 Sep 22:101413. doi: 10.1016/j.cpcardiol.2022.101413. Online ahead of print.

ABSTRACT

Mitral Regurgitation (MR) is the most common form of severe valvular disease occurring in developed countries, being caused either primarily on its own or secondary to cardiac disease. Surgical intervention is required for the correction of MR, which could include the replacement or repair of the affected valve. Transcatheter Mitral Valve Replacement (TMVR) in selected patients is of increasing importance, especially after the success of Transcatheter Aortic Valve Replacement (TAVR). TMVR can be divided into three types i.e., valve-in-valve (ViV) for severe mitral valve disease, valve-in-ring (ViR) for failed surgical repairs, and valve-in-mitral annular calcifications (ViMAC) for mitral valvular disease with severe mitral annular calcifications and poor surgical criteria. The FDA approved Mitral ViV for patients with a high surgical risk in 2017, while ViR and ViMAC are still currently under consideration. The SAPIEN M3 valve is relatively new with a trans-septal system, with a success rate of 86%, and no mortality in a 30-day outcome. The Cardiovalve is a bovine pericardium device that has a dual nitinol frame with a custom surgical design to facilitate TMVR. The AHEAD trial will evaluate whether the device is safe to use in a clinical setting and how effective it is for reducing MR in these patients. The trial consists of 30 patients in which the first 5 patients showed 100% technical success and a reduction of MR. This evolution of modern medicine has assisted in many different countries, including Pakistan where there is a higher prevalence of MR and hence, a greater need to apply TMVR in clinical practice.

PMID:36155202 | DOI:10.1016/j.cpcardiol.2022.101413

J Card Surg. 2022 Sep 23. doi: 10.1111/jocs.16847. Online ahead of print.

ABSTRACT

BACKGROUND: The average living age of the population is constantly increasing and so is the incidence and prevalence of aortic valve disease. Surgical aortic valve replacement (SAVR) is the current gold standard treatment. Nevertheless, the use of prosthetic valves in SAVR is associated with issues that impact patients’ quality of life. Aortic valve neocuspidization (AV Neo) offers a means to solve this dilemma by minimizing foreign valve tissue. AV Neo can either be performed using glutaraldehyde-treated autologous pericardium (Ozaki procedure) or bovine pericardium (Batista procedure).

AIMS: This commentary aims to discuss the recent study by Chan and colleagues which highlighted the surgical approach, clinical outcomes, and limitations of the Ozaki procedure, and compare this to the Batista procedure.

METHODS: A comprehensive literature search was performed using multiple electronic databases including PubMed, Ovid, Embase, and Scopus to collate the relevant research evidence.

RESULTS: Although the Ozaki procedure can achieve favorable results whilst mainly avoiding the need for life-long oral anticoagulation with mechanical valves, it still has several limitations that may hinder results. AV Neo using glutaraldehyde-treated bovine pericardium, developed by pioneer cardiac surgeon Dr. Randas J. Vilela Batista, yields superior clinical outcomes to Ozaki’s, including excellent survival, lower complications, and minimal need for reoperation as well as shorter operative times.

CONCLUSION: AV Neo offers a means to perform SAVR whilst escaping the prosthetic valve issues. However, the Batista procedure has shown beyond doubt that it can be considered the superior approach for AV Neo over the Ozaki procedure.

PMID:36150150 | DOI:10.1111/jocs.16847

Biomolecules. 2022 Sep 2;12(9):1222. doi: 10.3390/biom12091222.

ABSTRACT

Recent advancements in regenerative medicine have enhanced the development of biomaterials as multi-functional dressings, capable of accelerating wound healing and addressing the challenge of chronic wounds. Hydrogels obtained from decellularized tissues have a complex composition, comparable to the native extracellular environment, showing highly interesting characteristics for wound healing applications. In this study, a bovine pericardium decellularized extracellular matrix (dECM) hydrogel was characterized in terms of macromolecules content, and its immunomodulatory, angiogenic and wound healing potential has been evaluated. The polarization profile of human monocytes-derived macrophages seeded on dECM hydrogel was assessed by RT-qPCR. Angiogenic markers expression has been evaluated by Western blot and antibody array on cell lysates derived from endothelial cells cultured on dECM hydrogel, and a murine in vivo model of hindlimb ischemia was used to evaluate the angiogenic potential. Fibroblast migration was assessed by a transwell migration assay, and an in vivo murine wound healing model treated with dECM hydrogels was also used. The results showed a complex composition, of which the major component is collagen type I. The dECM hydrogel is biocompatible, able to drive M2 phenotype polarization, stimulate the expression of angiogenic markers in vitro, and prevent loss of functionality in hindlimb ischemia model. Furthermore, it drives fibroblast migration and shows ability to facilitate wound closure in vivo, demonstrating its great potential for regenerative applications.

PMID:36139063 | PMC:PMC9496624 | DOI:10.3390/biom12091222

Foot Ankle Surg. 2022 Sep 5:S1268-7731(22)00170-9. doi: 10.1016/j.fas.2022.08.013. Online ahead of print.

ABSTRACT

BACKGROUND: Hallux rigidus (HR) is a degenerative arthritis of the first metatarsophalangeal joint (MTP1) with progressive loss of range of movement (ROM). Interposition arthroplasty (IA) is a technique widely used for the treatment of HR;however, few studies reported long-term clinical results. This study aims to report the clinical results of IA using a bovine pericardium collagen matrix for HR with a minimum 10-years follow-up.

METHODS: Thirty patients (31 feet) who underwent IA using a bovine pericardium collagen matrix from 2001 to 2009 were retrospectively evaluated with a mean follow up of 154.1 ± 28.6 (range 124-218) months. All HR ranged from grade II to grade III, according to Regnauld classification. All patients were clinically assessed with the American Orthopedic Foot and Ankle Society Hallux Metatarsophalangeal- Interphalangeal Scale, a pain Visual Analog Scale, and the Foot and Ankle Disability Index. Scores before and after treatment, respectively achieved from clinical records and clinical evaluation at final follow-up were compared.

RESULTS: At final follow-up, an improvement of all the considered scores (p < 0.01) was recorded. The overall rate of unsatisfying results was 16.1 %. Two (6.4 %) patients complained discomfort due to first ray shortening and 3 (9.7 %) cases of persistent metatarsal pain. There was one (3.2 %) case of Complex Regional Pain Syndrome (CPRS). No revision surgeries, infection, or other adverse events were reported.

CONCLUSION: Interposition arthroplasty using bovine collagenous membrane is a reliable solution for high-grade HR with durable results over 10 years in more than 80 % of patients.

PMID:36117005 | DOI:10.1016/j.fas.2022.08.013

Biomaterials. 2022 Sep 6;289:121782. doi: 10.1016/j.biomaterials.2022.121782. Online ahead of print.

ABSTRACT

Bioprosthetic heart valves (BHV) fabricated from heterograft tissue, such as glutaraldehyde pretreated bovine pericardium (BP), are the most frequently used heart valve replacements. BHV durability is limited by structural valve degeneration (SVD), mechanistically associated with calcification, advanced glycation end products (AGE), and serum protein infiltration. We investigated the hypothesis that anti-AGE agents, Aminoguanidine, Pyridoxamine [PYR], and N-Acetylcysteine could mitigate AGE-serum protein SVD mechanisms in vitro and in vivo, and that these agents could mitigate calcification or demonstrate anti-calcification interactions with BP pretreatment with ethanol. In vitro, each of these agents significantly inhibited AGE-serum protein infiltration in BP. However, in 28-day rat subdermal BP implants only orally administered PYR demonstrated significant inhibition of AGE and serum protein uptake. Furthermore, BP PYR preincubation of BP mitigated AGE-serum protein SVD mechanisms in vitro, and demonstrated mitigation of both AGE-serum protein uptake and reduced calcification in vivo in 28-day rat subdermal BP explants. Inhibition of BP calcification as well as inhibition of AGE-serum protein infiltration was observed in 28-day rat subdermal BP explants pretreated with ethanol followed by PYR preincubation. In conclusion, AGE-serum protein and calcification SVD pathophysiology are significantly mitigated by both PYR oral therapy and PYR and ethanol pretreatment of BP.

PMID:36099713 | DOI:10.1016/j.biomaterials.2022.121782

Xenotransplantation. 2022 Sep 13:e12774. doi: 10.1111/xen.12774. Online ahead of print.

ABSTRACT

INTRODUCTION: Current bioprosthetic heart valve replacement options are limited by structural valvular deterioration (SVD) due to an immune response to the xenogenic scaffold. Autologous mesenchymal stem cell (MSC) recellularization is a method of concealing xenogenic scaffolds, preventing recipient immune recognition of xenogenic tissue heart valves, and potentially leading to reduction in SVD incidence. The purpose of this study is to examine the effects of autologous MSC recellularized tissue on the immune response of human whole blood to bovine pericardium (BP). We hypothesized that autologous MSC recellularization of BP will result in reduced pro-inflammatory cytokine production equivalent to autologous human pericardium.

METHODS: Bone marrow, human pericardium, and whole blood were collected from adult patients undergoing elective cardiac surgery. Decellularized BP underwent recellularization with autologous MSCs, followed by co-incubation with autologous whole blood. Immunohistochemical, microscopic, and quantitative immune analysis approaches were used.

RESULTS: We demonstrated that native BP, exposed to human whole blood, results in significant TNF-α and IL1β production. When decellularized BP is recellularized with autologous MSCs and exposed to whole blood, there is a significant reduction in TNF-α and IL1β production. Importantly, recellularized BP exposed to whole blood had similar production of TNF-α and IL1β when compared to autologous human pericardium exposed to human whole blood.

CONCLUSION: Our results suggest that preventing initial immune activation with autologous MSC recellularization may be an effective approach to decrease the recipient immune response, preventing recipient immune recognition of xenogeneic tissue engineered heart valves, and potentially leading to reduction in SVD incidence.

PMID:36098060 | DOI:10.1111/xen.12774