Organization of Collagen Fibers in the Intestine

Orberg, J.W.; Baer, E.; Hiltner, A.

doi:10.3109/03008208309004861

Cited by 60 publications

(23 citation statements)

References 17 publications

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“…Earlier results by Orberg 27,28 indicated two distinct fiber populations with ±30°fiber directions, which is in general agreement with our results. However, we also found that over most of the small intestine the SIS fiber orientation distribution was continuous.…”

Section: Discussionsupporting

confidence: 83%

Quantification of the fiber architecture and biaxial mechanical behavior of porcine intestinal submucosa

Sacks¹,

Gloeckner²

1999

J. Biomed. Mater. Res.

143

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Porcine small intestinal submucosa (SIS) has been shown to serve as a remodelable tissue scaffold in a wide range of applications. Despite the large number of experimental studies, there is a lack of fundamental information on SIS anisotropic mechanical behavior and how this behavior changes postimplantation. As a first step in our study of remodeling biomaterials, we performed biaxial mechanical testing to quantify the anisotropic mechanical behavior and used small-angle light scattering (SALS) to quantify the gross fiber structure of fresh, unimplanted SIS. Structural results indicate that SIS displays primarily a single, continuous preferred fiber direction oriented parallel to the long axis of the intestine. Occasionally, two distinct fiber populations oriented at approximately +/-28 degrees with respect to the longitudinal axis could be distinguished. Consistent with this structure, SIS exhibited a nonlinear, anisotropic mechanical response with higher stresses along the longitudinal axis. Further, the circumferential stress-strain response was strongly affected by the maximum longitudinal strain level, but the maximum circumferential strain level only weakly affected the longitudinal stress-strain response. This asymmetric mechanical coupling suggests strong mechanical interactions on a fiber level. SIS stress-strain response also was similar to glutaraldehyde-treated bovine pericardium, attesting to the substantial strength of SIS in the fresh, untreated state. The results of this study will provide a basis for a future analysis of the structural and mechanical changes during the remodeling process.

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Section: Discussionsupporting

confidence: 83%

Quantification of the fiber architecture and biaxial mechanical behavior of porcine intestinal submucosa

Sacks¹,

Gloeckner²

1999

J. Biomed. Mater. Res.

143

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“…Considering the huge increase in wall thickness after obstruction, it is evident that the total increase in collagen content is much higher than the density. The main physiological function of collagen in the tissues is to resist distending forces, i.e., to function in a protecting and stabilizing manner, or to transmit forces, i.e., to act as a link between components of the contractile system [27][28][29]. The compensatory increase in wall thickness and collagen content is likely a biological countermeasure to protect the intestine from bursting at high wall stresses.…”

Section: Discussionmentioning

confidence: 98%

Spontaneous and Bolus-induced Motility in the Chronically Obstructed Guinea-Pig Small Intestine In vitro

2007

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Partial obstruction of the small intestine results in dysmotility and morphometric changes proximal to the site of obstruction. However, our understanding of the relation between the morphometric remodeling and change in the motility pattern during chronic obstruction is sparse. The aim of this study was to investigate the effect of partial chronic intestinal obstruction on motility, morphology, and collagen content proximal and distal to the site of obstruction. Twenty guinea-pigs with partial intestinal obstruction and eight sham-operated controls lived for four weeks. Spontaneous and bolus-induced motility was recorded in isolated intestinal segments proximal and distal to the site of obstruction using a perfused low-compliance pressure-measuring system in vitro. After the motility experiments, the specimens were fixed at 2 kPa luminal distension pressure and sampled for histomorphometric determination of luminal radius, layer thickness, and wall thickness. Total wall collagen was also determined. The area under the curve (AUC) of spontaneous contractions and the amplitude, frequency, and AUC for the bolus-induced motility were higher in the proximal segments of the banded animals compared to distal segments and to the intestinal segments in the control animals (P < 0.05). The radius-to-thickness ratio was lowest in the proximal segments of the obstructed animals (P < 0.01). The collagen content was three times higher proximal to the site of obstruction when compared to distal locations and to the controls (P < 0.01). The AUC at 2 ml bolus injections plotted against the radius-to-thickness ratio showed a strong association (r = 0.97 for control, and r = 0.99 for obstruction, P < 0.01). No correlation was found between the collagen content and AUC. In conclusion, partial intestinal obstruction in guinea pigs caused pronounced changes in morphology and motility. An association was found between the radius-to-thickness ratio and bolus-induced motility.

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“…A derangement in ≥ 1 of these factors of the collagenous matrix may provoke a significant structural and functional disturbance in the organ. The main physiologic function of collagen in the tissues is to resist distending forces (function in a protecting and stabilizing manner) or to transmit forces (to act as a link between components of the contractile system [33][34][35]). Studies on arterial elastic properties have shown that collagen, the major extracellular structural protein, is responsible for the increased wall stiffness at physiologic and larger loads [36], as well as in pathologic conditions such as diabetes [37].…”

Section: Discussionmentioning

confidence: 99%

Biomechanical Remodeling of the Chronically Obstructed Guinea Pig Small Intestine

et al. 2007

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Small intestinal obstruction is a frequently encountered clinical problem. To understand the mechanisms behind obstruction and the clinical consequences, data are needed on the relation between the morphologic and biomechanical remodeling that takes place in the intestinal wall during chronic obstruction. We sought to determine the effect of partial obstruction on mechanical and morphologic properties of the guinea pig small intestine. Partial obstruction was created surgically in 2 groups of animals living for 2 and 4 weeks. Controls were sham operated and lived for 4 weeks. A combined impedance planimetry-high-frequency ultrasound system was designed to measure the luminal cross-sectional area and wall thickness. These measures were used to compute the circumferential stress and strain of the excised intestinal segments. The incremental elastic modulus was obtained by using nonlinear fitting of the stress-strain curve. Histologic analysis and the measurements of total wall collagen were also performed. The luminal cross-sectional area, wall thickness, and elastic modulus in circumferential direction increased in a time-dependent manner proximal to the obstruction site (P < 0.01), whereas no differences in these parameters were found distal to the obstruction site (P > 0.25). The circumferential stress-strain curves of the proximal segments in 2- and 4-week groups shifted to the left, indicating the intestinal wall became stiffer. Histologic examination revealed a massive increase in the thickness of the muscle layer especially the circular smooth muscle layer (P < 0.05). The collagen content proximal to the obstruction site was significantly larger in the partially obstructed animals compared to controls (P < 0.05). No difference was found distal to the obstruction site. Strong correlation was found between the collagen content and the elastic modulus at stress levels of 70 kPa stress (P < 0.01) and 10 kPa (P < 0.05) proximal to the obstruction site suggesting that the alteration of collagen has great impact on the mechanical remodeling. The morphologic and biomechanical remodeling likely influence the function of the intestine affected by partial obstructed intestine.

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Organization of Collagen Fibers in the Intestine

Cited by 60 publications

References 17 publications

Quantification of the fiber architecture and biaxial mechanical behavior of porcine intestinal submucosa

Quantification of the fiber architecture and biaxial mechanical behavior of porcine intestinal submucosa

Spontaneous and Bolus-induced Motility in the Chronically Obstructed Guinea-Pig Small Intestine In vitro

Biomechanical Remodeling of the Chronically Obstructed Guinea Pig Small Intestine

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