Impact on Mechanical Properties of 10 versus 20 Minute Treatment of Human Pericardium with Glutaraldehyde in OZAKI Procedure.
Ontology highlight
ABSTRACT: Purpose
The aim of this study was to analyze the effects of 10-minute (standard term) versus 20-minute treatment with glutaraldehyde (GA) on mechanical stability and physical strength of human pericardium in the setting of the OZAKI procedure.Methods
Leftover pericardium (6 patients) was bisected directly after the operation, and one-half was further fixed for 10 additional minutes. Uniaxial tensile tests were performed and ultimate tensile strength (UTS), ultimate tensile strain (uts), and collagen elastic modulus were evaluated.Results
Both treatments resulted in similar values of uniaxial stretching-generated elongations at rupture (10 minutes 25 ± 7 % vs. 20 minutes: 22 ± 5 %; p = 0.05), UTS (5.16 ± 2 MPa vs. 6.54 ± 3 MPa; p = 0.59), and collagen fiber stiffness (elastic modulus: 31.80 ± 15.05 MPa vs. 37.35 ± 15.78 MPa; p = 0.25).Conclusion
Prolongation of the fixation time of autologous pericardium has no significant effect on its mechanical stability; thus, extending the intraoperative treatment cannot be recommended.
SUBMITTER: Koechlin L
PROVIDER: S-EPMC8374088 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:BackgroundRheumatic valve disease (RVD) is the most common cause of cardiovascular death in low-middle income nations. Surgical aortic valve (AV) interventions for RVD, especially in children, have proven problematic with graft failure, relapse, and poor compliance with anticoagulation. A novel technique involving neocuspidization of the aortic annulus using autologous pericardium to construct new AV leaflets (the Ozaki procedure) has shown promising outcomes in children with congenital AV disease; however, there are no previous recorded cases using this technique in children with RVD.Case summaryWe present the case of a 15-year-old male presenting with exertional angina and dyspnoea with a background of previous rheumatic fever. Echocardiography had shown a regurgitant tricuspid AV, left ventricular dilatation with mitral valve leaflet tethering. The patient underwent the Ozaki procedure for his AV regurgitation and was discharged following an uneventful post-operative recovery. The patient had full resolution of symptoms following the procedure and remains well 3 years following his operation.DiscussionThis case highlights that good outcomes with the Ozaki procedure in RVD are possible 3-years post-operatively and should prompt future studies to evaluate the procedure as a surgical option for paediatric patients in this clinical context. Additionally, the Ozaki procedure may also provide a cost-effective surgical technique requiring minimal additional operative resources and reduced follow-up demand, which would be critical in low-resource clinical settings where RVD is prevalent.
| S-EPMC8274643 | biostudies-literature
Project description: Not available
| S-EPMC8302910 | biostudies-literature
Project description:OBJECTIVE:To determine the feasibility of aortic valve neocuspidization (AVNeo) with glutaraldehyde-treated autologous pericardium. METHODS:One hundred and seventy (170) AVNeo (84 males/86 females) were performed from January 2017 through March 2019 in three centers. All the records were prospectively collected and retrospectively reviewed. RESULTS:Most of the patients were older than 60 years and over 95% were operated for aortic stenosis. Preoperatively, pressure gradients were 69.9±21.3 mmHg for patients with aortic stenosis, and the surgical annular diameter was 21.0±2.0 mm for all patients. Effective orifice area (EOA) and indexed EOA (iEOA) averaged 0.7±0.3 cm2 and 0.4±0.2 cm2/m2 for patients with aortic stenosis before surgery, respectively. There was no conversion to prosthetic aortic valve replacement. Eight patients needed reoperation for bleeding, but no patient needed reoperation due to early infective endocarditis. There were five in-hospital deaths due to noncardiac cause. Compared to preoperative echocardiographic measurements, postoperative peak pressure gradient decreased significantly (-58.7±1.7 mmHg; P<0.001) and reached 11.2±5.6 mmHg, and mean pressure gradient also decreased significantly (-36.8±1.1 mmHg; P<0.001) and reached 6.0±3.5 mmHg. Accordingly, EOA and iEOA increased significantly 2.0 cm2 and 1.0 cm2/m2 (both P<0.001) to reach 2.7±0.6 cm2 and 1.4±0.3 cm2/m2 after surgery, respectively, with minimal significant aortic regurgitation (0.6% > mild). CONCLUSION:AVNeo is feasible and reproducible with good clinical results. Hemodynamically, AVNeo produces immediate postoperative low-pressure gradients, large EOA, and minimal regurgitation of the aortic valve. Further studies are necessary to evaluate mid- and long-term evolution.
| S-EPMC7299575 | biostudies-literature
Project description:Much attention has been focused on the passive mechanical properties of the myocardium, which determines left ventricular (LV) diastolic mechanics, but the significance of the visceral pericardium (VP) has not been extensively studied. A unique en face three-dimensional volumetric view of the porcine VP was obtained using two-photon excitation fluorescence to detect elastin and backscattered second harmonic generation to detect collagen, in addition to standard light microscopy with histological staining. Below a layer of mesothelial cells, collagen and elastin fibers, extending several millimeters, form several distinct layers. The configuration of the collagen and elastin layers as well as the location of the VP at the epicardium providing a geometric advantage led to the hypothesis that VP mechanical properties play a role in the residual stress and passive stiffness of the heart. The removal of the VP by blunt dissection from porcine LV slices changed the opening angle from 53.3 +/- 10.3 to 27.3 +/- 5.7 degrees (means +/- SD, P < 0.05, n = 4). In four porcine hearts where the VP was surgically disrupted, a significant decrease in opening angle was found (35.5 +/- 4.0 degrees ) as well as a rightward shift in the ex vivo pressure-volume relationship before and after disruption and a decrease in LV passive stiffness at lower LV volumes (P < 0.05). These data demonstrate the significant and previously unreported role that the VP plays in the residual stress and passive stiffness of the heart. Alterations in this layer may occur in various disease states that effect diastolic function.
| S-EPMC2878718 | biostudies-literature
Project description:There is a significant need for fixed biological tissues with desired structural and material constituents for tissue engineering applications. Here, we introduce the lung ligament as a fixed biological material that may have clinical utility for tissue engineering. To characterize the lung tissue for potential clinical applications, we studied glutaraldehyde-treated porcine pulmonary ligament (n = 11) with multiphoton microscopy (MPM) and conducted biaxial planar experiments to characterize the mechanical property of the tissue. The MPM imaging revealed that there are generally two families of collagen fibers distributed in two distinct layers: The first family largely aligns along the longitudinal direction with a mean angle of ? = 10.7 ± 9.3 deg, while the second one exhibits a random distribution with a mean ? = 36.6 ± 27.4. Elastin fibers appear in some intermediate sublayers with a random orientation distribution with a mean ? = 39.6 ± 23 deg. Based on the microstructural observation, a microstructure-based constitutive law was proposed to model the elastic property of the tissue. The material parameters were identified by fitting the model to the biaxial stress-strain data of specimens, and good fitting quality was achieved. The parameter e0 (which denotes the strain beyond which the collagen can withstand tension) of glutaraldehyde-treated tissues demonstrated low variability implying a relatively consistent collagen undulation in different samples, while the stiffness parameters for elastin and collagen fibers showed relatively greater variability. The fixed tissues presented a smaller e0 than that of fresh specimen, confirming that glutaraldehyde crosslinking increases the mechanical strength of collagen-based biomaterials. The present study sheds light on the biomechanics of glutaraldehyde-treated porcine pulmonary ligament that may be a candidate for tissue engineering.
| S-EPMC7104758 | biostudies-literature
Project description:A cell's mechanical properties are important in determining its adhesion, migration, and response to the mechanical properties of its microenvironment and may help explain behavioral differences between normal and cancerous cells. Using fluorescently labeled peroxisomes as microrheological probes, the interior mechanical properties of normal breast cells were compared to a metastatic breast cell line, MDA-MB-231. To estimate the mechanical properties of cell cytoplasms from the motions of their peroxisomes, it was necessary to reduce the contribution of active cytoskeletal motions to peroxisome motion. This was done by treating the cells with blebbistatin, to inhibit myosin II, or with sodium azide and 2-deoxy-D-glucose, to reduce intracellular ATP. Using either treatment, the peroxisomes exhibited normal diffusion or subdiffusion, and their mean squared displacements (MSDs) showed that the MDA-MB-231 cells were significantly softer than normal cells. For these two cell types, peroxisome MSDs in treated and untreated cells converged at high frequencies, indicating that cytoskeletal structure was not altered by the drug treatment. The MSDs from ATP-depleted cells were analyzed by the generalized Stokes-Einstein relation to estimate the interior viscoelastic modulus G* and its components, the elastic shear modulus G' and viscous shear modulus G", at angular frequencies between 0.126 and 628 rad/s. These moduli are the material coefficients that enter into stress-strain relations and relaxation times in quantitative mechanical models such as the poroelastic model of the interior regions of cancerous and non-cancerous cells.
| S-EPMC4984850 | biostudies-literature
Project description:Extracellular matrix bioscaffolds can influence the cardiac microenvironment and modulate endogenous cellular mechanisms. These materials can optimize cardiac surgery for repair and reconstruction. We investigated the biocompatibility and bioinductivity of bovine pericardium fixed via dye-mediated photo-oxidation on human cardiac fibroblast activity. We compared a dye-mediated photo-oxidation fixed bioscaffold to glutaraldehyde-fixed and non-fixed bioscaffolds reported in contemporary literature in cardiac surgery. Human cardiac fibroblasts from consenting patients were seeded on to bioscaffold materials to assess the biocompatibility and bioinductivity. Human cardiac fibroblast gene expression, secretome, morphology and viability were studied. Dye-mediated photo-oxidation fixed acellular bovine pericardium preserves human cardiac fibroblast phenotype and viability; and potentiates a pro-vasculogenic paracrine response. Material tensile properties were compared with biomechanical testing. Dye-mediated photo-oxidation fixed acellular bovine pericardium had higher compliance compared to glutaraldehyde-fixed bioscaffold in response to tensile force. The biocompatibility, bioinductivity, and biomechanical properties of dye-mediated photo-oxidation fixed bovine pericardium demonstrate its feasibility as a bioscaffold for use in cardiac surgery. As a fixed yet bioinductive solution, this bioscaffold demonstrates enhanced compliance and retains bioinductive properties that may leverage endogenous reparative pathways. Dye-mediated photo-oxidation fixed bioscaffold warrants further investigation as a viable tool for cardiac repair and reconstruction.
| S-EPMC8509588 | biostudies-literature
Project description:BACKGROUND: The pericardial tissue is commonly used to produce bio-prosthetic cardiac valves and patches in cardiac surgery. The procedures adopted to prepare this tissue consist in treatment with aldehydes, which do not prevent post-graft tissue calcification due to incomplete xeno-antigens removal. The adoption of fixative-free decellularization protocols has been therefore suggested to overcome this limitation. Although promising, the decellularized pericardium has not yet used in clinics, due to the absence of proofs indicating that the decellularization and cryopreservation procedures can effectively preserve the mechanical properties and the immunologic compatibility of the tissue. PRINCIPAL FINDINGS: The aim of the present work was to validate a procedure to prepare decellularized/cryopreserved human pericardium which may be implemented into cardiovascular homograft tissue Banks. The method employed to decellularize the tissue completely removed the cells without affecting ECM structure; furthermore, uniaxial tensile loading tests revealed an equivalent resistance of the decellularized tissue to strain, before and after the cryopreservation, in comparison with the fresh tissue. Finally, immunological compatibility, showed a minimized host immune cells invasion and low levels of systemic inflammation, as assessed by tissue transplantation into immune-competent mice. CONCLUSIONS: Our results indicate, for the first time, that fixative-free decellularized pericardium from cadaveric tissue donors can be banked according to Tissue Repository-approved procedures without compromising its mechanical properties and immunological tolerance. This tissue can be therefore treated as a safe homograft for cardiac surgery.
| S-EPMC3660606 | biostudies-literature
Project description:ObjectiveThis post-hoc analysis compared the lipid-altering efficacy of Ezetimibe/Simvastatin 10/20 mg (EZ/Simva) versus Rosuvastatin 10 mg (Rosuva) in patients stratified by statin potency/dose prior to randomization.MethodsPatients with elevated low-density lipoprotein cholesterol (LDL-C) despite prior statin treatment (n=618) were randomized 1:1 to EZ/Simva 10/20 mg or Rosuva 10 mg for 6 weeks. Percent change from baseline in lipids and attainment of lipid targets were assessed within each subgroup (low potency n=369, high potency n=249). Consistency of the treatment effect across subgroups was evaluated by testing for treatment-by-subgroup interaction. No multiplicity adjustments were made.ResultsSignificant treatment-by-subgroup interaction occurred for LDL-C (p=0.013), total cholesterol (p=0.025), non-HDL-C (p=0.032), and apolipoprotein B (p=0.016) with greater between-treatment differences in favor of EZ/Simva observed in patients from the high potency stratum vs low potency stratum. Individual and triple target attainment was higher for Eze/Simva compared with Rosuva in both strata.ConclusionsCompared with Rosuva, switching to EZ/Simva provided greater reductions in LDL-C, total cholesterol, non-HDL-C and apolipoprotein B and higher target attainment in patients on prior statin treatment, regardless of potency, although patients treated with higher potency statins prior to randomization experienced greater between treatment differences in favor of EZ/Simva.Trial registrationRegistered at ClinicalTrials.gov: NCT00479713.
| S-EPMC2992529 | biostudies-literature
Project description:Functional tests such as Motor Function Measure-32 (MFM-32), supine to stand, ascend/descend stairs permit the assessment of task-specific motor function in neuromuscular disease (NMD). The 6-min walk test (6MWT), though functional, is primarily used to assess endurance and disease progression in children with neuromuscular disorders. Barriers to 6MWT administration, in this population, can include reduced attention span due to age and inability to tolerate test length due to weakness. We propose task-specific functional deficits are related to endurance. Additionally, the 2-min walk test (2MWT) could effectively replace the 6MWT in this population. Seventy-seven participants, ages 5-18, with a variety of neuromuscular disorders performed the 6MWT, timed functional tests (TFT), and the MFM-32. Correlation and paired t-test analyses were used to compare the distance walked in the first 2 min (2MWD) to the distance walked in the entire 6 min (6MWD) and to the functional outcome measures above. The 2MWD strongly correlated with 6MWD and the other outcome measures. Paired t-test analysis also showed that the 2MWD did not differ from the distance walked in the last 2 min of the 6MWT. Although equivalence testing could not reject the claim that this difference exceeded the upper practical limit of 9.5 m, it only showed a modest overestimation of the 4-6MWD compared with the 2MWD. Together, our results support the ability of the 2MWD to predict the 6MWD, specifically in the pediatric neuromuscular disease population.
| S-EPMC6423958 | biostudies-literature