Multimodal investigation of a keloid scar by combining mechanical tests in vivo with diverse imaging techniques

Abstract

Keloids are pathologic scars, defined as fibroproliferative diseases resulting from abnormal wound responses, which grow beyond the original wound margins. They develop on specific pro-keloid anatomic sites frequently characterized by high stress states. The initiation and growth mechanisms of keloid are not well-understood. This study relates multimodal investigation of a keloid by using mechanical tests in vivo and imaging techniques. A single case composed of a keloid, the healthy skin surrounding the keloid, and the contralateral healthy skin on the upper arms of a woman has been investigated in extension and suction by using non-invasive devices dedicated to in vivo skin measurement. The thickness and microstructure of these soft tissues have been observed by echography, tomography and confocal microscopy. Displacement fields 1 have been obtained by using digital image correlation. Unlike healthy skin, keloid is not a well-defined multilayer structure: the frontier between epidermis and dermis disappears. The mechanical behavior of keloid is highly different from healthy skin one. The R-parameters have been deduced from suction curves. Physical parameters as tissue extensibility, initial and final tangent moduli have been identified from the stress-strain curves. The extensibility (respectively, initial rigidity) of keloid is highly lower (respectively, higher) than that of healthy skin. To compare the final rigidity of keloid versus healthy skin, further tests have to be performed with higher strain values.

The Human Epidermal Basement Membrane: A Shaped and Cell Instructive Platform That Aging Slowly Alters

“…In severe recessive dystrophic epidermolysis bullosa (EB)-affected skin in which the anchoring fibrils component collagen VII is defective, rete ridges are normal before epidermal blister formation but are affected during the resolution of the blister, and hyperkeratosis with scarring reduces rete ridges [59]. A flattening of the DEJ is also observed in cheloids, pathologic scars defined as fibroproliferative diseases resulting from abnormal wound responses, which grow beyond the original wound margins [60]. Interesting studies, however, have reported rete ridge regeneration after full or partial-thickness wounding in a few animal models, such as the Red Duroc and Lanyu pigs [61][62][63].…”

An open-source FEniCS-based framework for hyperelastic parameter estimation from noisy full-field data: Application to heterogeneous soft tissues

“…The numerical process developed in order to identify bi-material soft tissue parameters is based on a Finite Element Method Updating inverse problem, where we simulate the in vivo uniaxial tensile test performed on human skin. Our focus is on a butterfly-shaped keloid scar situated on the left upper arm of a Caucasian skin presented by Chambert et al [63]. From that uniaxial test (Fig.…”

“…As a case study, we simulate the in vivo uniaxial test performed with a light extensometer on a bi-material media. The model consists of an heterogeneity (keloid) surrounded by healthy skin, as described in the following studies: Jacquet et al [62] and Chambert et al [63]. Keloids are benign tumours growing continuously and progressively over the human skin surface [64].…”

“…Keloids are benign tumours growing continuously and progressively over the human skin surface [64]. The evolution of keloids is known to be related to many factors, biological, genetic and biomechanical [63,65]. Beside the psychosocial effects caused by the unpleasant keloidic shapes, such as anxiety and depression, keloid tumours tend to limit the motion of surrounding skin because they are stiffer and more isotropic.…”

End-user Need based Creation of a Medical Device: An Experience of Co-design to Struggle Pathological Scars

“…The secondary objectives of the Scar Wars trial focused on a multimodal and interdisciplinary assessment of scar tissues by (Chambert et al, 2019): -evaluation of patient acceptance and satisfaction, evaluation by the surgeon (specific scars evaluation scales, Draaijers et al, 2004, Deslauriers et al, 2009, -biometric characterization of the area of interest, -non-invasive imaging assessment of tissue evolution, -analysis of the bacterial flora present at the level of the keloid scar, -the creation of a keloid cell bank, basis of a biological ancillar study allowing our biologists to focus on pathological healing process and antifibrotic drug evaluation.…”