Functional implications of myocardial scar structure

1997 ◽  
Vol 272 (5) ◽  
pp. H2123-H2130 ◽  
Author(s):  
J. W. Holmes ◽  
J. A. Nunez ◽  
J. W. Covell
Keyword(s):  
Collagen Fiber ◽  
Circumferential Strain ◽  
Important Determinant ◽  
Scar Tissue ◽  
Collagen Fibers ◽  
Myocardial Scar ◽  
Radial Deformation ◽  
Fiber Structure ◽  
Coronary Ligation ◽  
Functional Implications

During healing after myocardial infarction, scar collagen content and stiffness do not correlate. We studied regional mechanics and both area fraction and orientation of large collagen fibers 3 wk after coronary ligation in the pig. During passive inflation of isolated, arrested hearts, the scar tissue demonstrated significantly less circumferential strain but similar longitudinal and radial deformation in comparison with noninfarcted regions of the same hearts. The observed selective resistance to circumferential deformation was consistent with the finding that most of the large collagen fibers in the scar were oriented within 30 degrees of the local circumferential axis. Furthermore, data from a previous study indicate that during ventricular systole these scars resist circumferential stretching, whereas they deform similarly to noninfarcted myocardium in the longitudinal and radial directions. We conclude that large collagen fiber structure is an important determinant of scar mechanical properties and that scar anisotropy allows the scar to resist circumferential stretching while deforming compatibly with adjacent noninfarcted myocardium in the longitudinal and radial directions.

Collagen Fiber Structure Correlates With Mechanical Environment in Healing Myocardial Infarcts

2009 ◽  
Author(s):  
Gregory M. Fomovsky ◽  
Jeffrey W. Holmes
Keyword(s):  
Mechanical Properties ◽  
Ventricular Function ◽  
Rat Model ◽  
Collagen Fiber ◽  
Important Determinant ◽  
Collagen Fibers ◽  
Anisotropic Structure ◽  
Fiber Structure ◽  
Mechanical Environment ◽  
Time Points

Mechanics of healing myocardial infarcts are an important determinant of ventricular function. Large collagen fibers are the major contributors to the mechanical properties of healing scar. It has been suggested that an anisotropic structure, as observed in healing pig scars, may help preserve ventricular function, and that the alignment of collagen fibers could be guided by the regional mechanical environment in the infarct — in pig scars the alignment of collagen fibers was in the direction of greatest stretch [1]. By contrast, in the standard rat model of infarction we found that scars are structurally and mechanically isotropic at all time points in healing [2].

Fiber-Based Constitutive Model of Myocardial Scar Tissue

2007 ◽  
Author(s):  
Dezba G. Coughlin ◽  
Gregory M. Fomovsky ◽  
Jeffrey W. Holmes
Keyword(s):  
Structural Analysis ◽  
Constitutive Model ◽  
Collagen Fiber ◽  
Scar Tissue ◽  
Collagen Fibers ◽  
Myocardial Scar ◽  
Structural Basis ◽  
Myocardial Scar Tissue

It has largely been accepted that collagen fibers play an important role in the mechanics of myocardial scar tissue; however, few studies have performed both mechanical and structural analysis on the same samples to confirm this. Therefore, the goal of this study was to combine both types of analysis with a structure-based constitutive model, which incorporates measured collagen fiber orientations, to gain a better understanding of the structural basis for the mechanics of two-week-old scar tissue.

scholarly journals Collagen Fibers-based Self-assembled 3D Spheroids Alleviate Thioacetamide-induced Liver Cirrhosis in Rats

2021 ◽  
Author(s):  
Yu Chiuan Wu ◽  
Guan Xuan Wu ◽  
Kuan Wei Chen ◽  
Li-Yen Shiu ◽  
Satheesh Kumar ◽  
...  
Keyword(s):  
Liver Cirrhosis ◽  
Liver Function ◽  
Liver Damage ◽  
Collagen Fiber ◽  
Scar Tissue ◽  
Collagen Fibers ◽  
Paracrine Factor ◽  
Self Assembled ◽  
Hepatocyte Spheroids ◽  
3D Spheroids

Abstract Cirrhosis refers to irreversible liver damage where healthy tissue is replaced by scar tissue which impairs liver function. There is no cure and current treatments only prevent further liver damage; thus novel therapeutic options are urgently needed. Here, we report a new approach that enables the formation of the self-assembled 3D spheroids of adipose-derived stem cells (ADSCs) and murine hepatocytes (AML12) via reconstituted collagen fibers. Compared with the spheroids formed in the commercially available EZSHERE dish, the collagen fiber-based ADSC/hepatocyte spheroids offer a notable benefit in structure formation and paracrine factor secretion. To test regenerative capability of the collagen fiber-based 3D ADSC/hepatocyte spheroids, a rat model of thioacetamide (TAA)-induced liver cirrhosis was employed. The transplantation of the collagen fiber-based 3D ADSC/hepatocyte spheroids show an improvement in liver function and ameliorates pathological liver cirrhosis in TAA-treated rats. In summary, our data show collagen fiber-based self-assembled 3D ADSC/hepatocyte spheroids to possess excellent regenerative capacity in response to TAA-induced liver injury, promising an alternative therapeutic strategy for liver cirrhosis.

A Review of the Collagen Orientation in the Articular Cartilage

Cartilage ◽  
2021 ◽  
pp. 194760352098877
Author(s):  
Roy D. Bloebaum ◽  
Andrew S. Wilson ◽  
William N. Martin
Keyword(s):  
Surface Layer ◽  
Articular Cartilage ◽  
Fiber Orientation ◽  
Collagen Fiber ◽  
Articular Surface ◽  
Imaging Techniques ◽  
Collagen Fibers ◽  
Deep Zone ◽  
Collagen Fiber Orientation ◽  
Critical Point Drying

Objective There has been a debate as to the alignment of the collagen fibers. Using a hand lens, Sir William Hunter demonstrated that the collagen fibers ran perpendicular and later aspects were supported by Benninghoff. Despite these 2 historical studies, modern technology has conflicting data on the collagen alignment. Design Ten mature New Zealand rabbits were used to obtain 40 condyle specimens. The specimens were passed through ascending grades of alcohol, subjected to critical point drying (CPD), and viewed in the scanning electron microscope. Specimens revealed splits from the dehydration process. When observing the fibers exposed within the opening of the splits, parallel fibers were observed to run in a radial direction, normal to the surface of the articular cartilage, radiating from the deep zone and arcading as they approach the surface layer. After these observations, the same samples were mechanically fractured and damaged by scalpel. Results The splits in the articular surface created deep fissures, exposing parallel bundles of collagen fibers, radiating from the deep zone and arcading as they approach the surface layer. On higher magnification, individual fibers were observed to run parallel to one another, traversing radially toward the surface of the articular cartilage and arcading. Mechanical fracturing and scalpel damage induced on the same specimens with the splits showed randomly oriented fibers. Conclusion Collagen fiber orientation corroborates aspects of Hunter’s findings and compliments Benninghoff. Investigators must be aware of the limits of their processing and imaging techniques in order to interpret collagen fiber orientation in cartilage.

Collagen Fiber Morphology Determines Echogenicity of Myocardial Scar: Implications for Image Interpretation

2006 ◽  
Vol 23 (2) ◽  
pp. 103-107 ◽  
Author(s):  
Ghasan M. Tabel ◽  
Peter Whittaker ◽  
Konstantinos Vlachonassios ◽  
Mehul Sonawala ◽  
P. Anthony Chandraratna
Keyword(s):  
Collagen Fiber ◽  
Image Interpretation ◽  
Myocardial Scar ◽  
Fiber Morphology

India Ink Pinprick Experiments on Surface Organization of Cricoarytenoid Joints

1986 ◽  
Vol 29 (4) ◽  
pp. 544-548 ◽  
Author(s):  
Joel C. Kahane ◽  
Alice R. Kahn
Keyword(s):  
Articular Cartilage ◽  
Collagen Fiber ◽  
Collagen Fibers ◽  
Articular Surfaces ◽  
India Ink ◽  
Age Related ◽  
Cricoarytenoid Joint ◽  
Mechanical Factors ◽  
Fiber Organization

Collagen fiber organization in the articular surfaces of the cricoarytenoid joint (CAJ) was studied using a pinpricking technique used in biomechanical research in orthopedics. Four male human formalin preserved specimens (3 months to 20 years) and 6 male freshly autopsied specimens (19 to 30 yrs) were studied. Specimens were dissected using the stereomicroscope. Distinctive patterns of articular cartilage slits reflect the orientation of collagen fibers in the cricoid and arytenoid articular surfaces. The orientation of the collagen fibers reinforces the articular surfaces along the principle path of CAJ motion. No age related differences were found. This suggests that the orientation of collagen fibers in the CAJ articular surfaces is prenatally determined rather than significantly influenced by postnatal mechanical factors.

scholarly journals Detection of myocardial scar tissue by M-mode echocardiography.

Circulation ◽  
1978 ◽  
Vol 57 (2) ◽  
pp. 230-237 ◽  
Author(s):  
S Rasmussen ◽  
B C Corya ◽  
H Feigenbaum ◽  
S B Knoebel
Keyword(s):  
Scar Tissue ◽  
Myocardial Scar ◽  
Myocardial Scar Tissue

scholarly journals Analysis of Segmental Strain for the Detection of Chronic Ischemic Scars in Non-Contrast Cardiac MRI Cine Images: A Feasibility Study

2020 ◽  
Author(s):  
Malgorzata Polacin ◽  
Mihaly Karolyi ◽  
Matthias Eberhard ◽  
Alexander Gotschy ◽  
Bettina Baessler ◽  
...  
Keyword(s):  
Wall Motion ◽  
Circumferential Strain ◽  
Radial Strain ◽  
Scar Tissue ◽  
Remote Myocardium ◽  
Healthy Individuals ◽  
Polar Plot ◽  
Global Strain ◽  
Motion Assessment ◽  
Global Peak

Abstract Aims Cardiac magnetic resonance imaging (MRI) with late gadolinium enhancement (LGE) is considered the gold standard for scar detection after myocardial infarction. In times of increasing skepticism about gadolinium depositions in brain tissue and contraindications of gadolinium administration in some patient groups, tissue strain-based techniques for detecting ischemic scars should be further developed as part of clinical protocols. Therefore, the objective of the present work was to investigate the feasibility of scar detection in segmental strain calculations based on routinely acquired non-contrast cine images in patients with chronic infarcts.Methods Forty-six patients with chronic infarcts and scar tissue in LGE images (5 female, mean age 52 ± 19 years) and 24 gender- and age- matched healthy controls (2 female, mean age 47 ± 13 years) were included. Global (global peak circumferential [GPCS], global peak longitudinal [GPLS], global peak radial strain [GPRS]) and segmental (segmental peak circumferential [SPCS], segmental peak longitudinal [SPLS], segmental peak radial strain [SPRS]) strain parameters were calculated from standard balanced SSFP cine sequences using commercially available software (Segment CMR, Medviso, Sweden). Two independent blinded readers localized potentially infarcted segments in segmental circumferential strain calculations (endo-/epicardially contoured short axis cine and resulting polar plot strain map) and by visual wall motion assessment of cine images. Results Global strain values were reduced in patients compared to controls (GPCS p= 0.02; GPLS p= 0.04; GPRS p= 0.01). Patients with preserved ejection fraction showed also reduced GPCS compared to healthy individuals (p=0.04). In patients, mean SPCS was significantly impaired in subendocardially (- 5,4% +/- 2) and in transmurally infarcted segments (- 1,2% ± 3) compared to remote myocardium (-12,9% +/- 3, p= 0.02 and 0.03, respectively). ROC analysis revealed an optimal cut- off value for SPCS for discriminating infarcted from remote myocardium of - 7,2 % with a sensitivity of 89,4 % and specificity of 85,7%. Mean SPRS was impeded in transmurally infarcted segments (15,9 % +/- 6) compared to SPRS of remote myocardium (31,4% +/- 5; p= 0.02). The optimal cut-off value for SPRS for discriminating scar tissue from remote myocardium was 16,6% with a sensitivity of 83,3% and specificity of 76,5%. 80.3 % of all in LGE infarcted segments (118/147) were correctly localized in segmental circumferential strain calculations based on non-contrast cine images compared to 53.7% (79/147) of infarcted segments detected by visual wall motion assessment (p > 0.01). Conclusion Global strain parameters are impaired in patients with chronic infarcts compared to healthy individuals. Mean SPCS and SPRS in scar tissue is impeded compared to remote myocardium in infarcts patients. Blinded to LGE images, two readers correctly localized 80% of infarcted segments in segmental circumferential strain calculations based on non-contrast cine images, in contrast to only 54% of infarcted segments detected by visual wall motion assessment. Analysis of segmental circumferential strain shows a promising alternative for scar detection based on routinely acquired, non-contrast cine images for patients who cannot receive or decline gadolinium.

Structural Characterization of a Biogenic Secretion Extracted from the Tendon or Ligament in Rabbits for Artificial Ligament Formation

2021 ◽  
Vol 1016 ◽  
pp. 786-791
Author(s):  
Toru Kuzumaki ◽  
Tatsuya Yamaguchi ◽  
Kengo Shimozaki ◽  
Junsuke Nakase ◽  
Kojun Torigoe
Keyword(s):  
Achilles Tendon ◽  
Collagen Fiber ◽  
Cross Linking ◽  
Fiber Structure ◽  
Collateral Ligament ◽  
Artificial Ligament ◽  
Model Method ◽  
Basic Investigation

Thus far, our research group has conducted a basic investigation for the development of an artificial ligament, which was performed by utilizing a biogenic secretion that was derived from the Achilles tendon in mice; this was achieved using the film model method. In this study, an attempt has been made to derive a biogenic secretion from the Achilles tendon (tendon gel) and the medial collateral ligament (ligament gel) in rabbits. Subsequently, a discussion was carried out on the possibility of forming a ligament-like structure that was based on the structural, mechanical, and spectroscopic investigations. The tendon gel was successfully formed from a parent tendon that was preserved in vivo for 3, 5, 10, and 15 d. Further, an aligned collagen fiber emerged in the tendon gel, which was subjected to tension on every preservation date. Further, the mechanical behavior of the tendon gel specimens was classified in two groups. The values of the Young's modulus of the specimens preserved for 10 and 15 d were higher than those of the specimens preserved for 3 and 5 d. Within the range of this experimental condition, the aligned collagen fiber structure was formed by applying a tension of approximately greater than 0.05 N. Conversely, only a 10-d preservation period yielded a sufficient amount of ligament gel for the experiment. Notably, the volume of ligament gel was less than that of the tendon gel. In the ligament gel specimen without the synovial membrane, the collagen fiber structure was formed by applying a tension, which was similar to that experienced by the tendon gel specimen. However, the cross-linking and growth of collagen fibers in the ligament gel samples were insignificant as compared with those of the tendon gel samples.

scholarly journals P1437 Integrated ST segment elevation score as a new predictor of the myocardial scar extent determined with LGE-CMR at 1-month follow-up after STEMI

2020 ◽  
Vol 21 (Supplement_1) ◽  
Author(s):  
A Mester ◽  
T Benedek ◽  
D Opincariu ◽  
A Benedek ◽  
M Ratiu ◽  
...  
Keyword(s):  
Scar Tissue ◽  
Myocardial Scar ◽  
St Segment Elevation ◽  
Elevation Score ◽  
St Segment ◽  
Myocardial Scar Tissue ◽  
Hs Crp ◽  
Lge Cmr

Abstract Funding Acknowledgements Funded by the research grant PlaqueImage, contract number 26/01.09.2016, SMIS code 103544, by the European Union and the Government of Romania Background The inflammatory response in the acute phase of a myocardial infarction, as well as in later phases contributes to the healing process of the infarcted myocardium and the left ventricular remodeling. Restoration and improvement of LV function highly depends on the magnitude of scar formation. Late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) imaging has been validated for an accurate determination of the myocardial scar size and transmurality. The recovery of ST segment elevation is a liable marker of vessel patency following PCI. Purpose The aim of the study was to validate a new integrated score of ST segment elevation score (ISSTE) as a new predictor of the myocardial scar tissue size, in relation with increased inflammatory biomarkers, with the extent of myocardial fibrosis at one month, assessed with LGE-CMR, after STEMI. Methods We included 65 patients with STEMI who underwent urgent revascularization with PCI in the first 12 hours from the onset of symptoms. The ISSTE was determined by summing the ST segment elevation in all registered ECG leads at presentation (ISSTE-1) and at 2 hours (ISSTE-2) after primary PCI. Blood samples were also collected at baseline and day-5 for determination of serum hs-CRP levels. At 1-month follow-up all patients under LGE-CMR (1.5T scanner) for evaluation of the myocardial scar extent (volume, percentage, transmurality). Results ISSTE-2 was significantly correlated with day-5 hs-CRP serum levels (r = 0.546, 95%CI: 0.030-0.832, p = 0.037), although no significant correlations were noted with baseline hs-CRP levels (r= 0.238, p = 0.407). There were no significant correlations between ISSTE-1 score and the myocardial scar percentage (r = 0.241, p = 0.11) or high transmurality volume (r = 0.194, p = 0.21), while ISSTE-2 significantly correlated with myocardial scar mass (r = 0.406, 95%CI: 0.107-0.637 p = 0.007) and high transmurality volume (r = 0.344, 95%CI: 0.0320-0.596, p = 0.0273). The restoration of the ST segment, reflected by the difference between ISSTE-1 and ISSTE -2 is correlated with the infarct size mass (r = 0.336, 95%CI: 0.0307 -0.584, p = 0.027). Conclusion The magnitude of ST segment elevation determined at 2 hours after PCI was associated with the inflammatory response at day 5 after STEMI and it may serve as a predictor for the extent of the myocardial scar tissue determined with LGE-CMR at 1 month following STEMI. The ISSTE-1 score calculated at presentation does not reflect extent of the affected myocardial tissue following PCI.

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