Contraction and myofibroblasts in restored skin

Healing and Normal Fibroblasts Exhibit Differential Proliferation, Collagen Production, α-SMA Expression, and Contraction

This study determines the differences in proliferation, collagen production, alpha-smooth muscle actin (alpha-SMA) expression, and contraction between healing and normal fibroblasts. Transected and sham-operated rat medial collateral ligaments (MCL) were used to obtain healing and normal fibroblasts, respectively. It was found that healing fibroblasts in monolayer culture proliferated 1.4-fold faster at 48 h and had 1.7-fold greater protein expression of alpha-SMA than normal fibroblasts. In addition, it was noted that the proliferation of healing fibroblasts in collagen gels was not significantly different from that of normal fibroblasts at 24 h, but it was at 48 h. Furthermore, in collagen gels, healing fibroblasts produced more type I collagen than normal fibroblasts and generated 1.6- and 1.7-fold larger contractile forces at 15 and 20 h, respectively, than their normal counterparts. Taken together, the results of this study show that healing fibroblasts possess a differential proliferation, alpha-SMA protein expression, and contraction than normal fibroblasts.

The problem of subepidermal blisters in neoformed integuments

The present paper is a review of articles on the onset of subepidermal blisters in neoformed integuments. Considering the discrepancy between the literature data and our clinical experience concerning spontaneous onset of subepidermal blisters in neoformed integuments, we decided to conduct an extensive review of the literature. The main finding arising from it was the lack of characterization of the neoformed integument where the blisters were formed. These were normally referred to only by clinical descriptions such as "spontaneously healed burn", "grafted site", "donor site", "epidermal graft". Anatomical and clinical pathology aspects such as the formation mechanism of these integuments and the respective tissues that comprise them were not considered. We concluded that by adopting more precise criteria to classify neoformed integuments we would realize that split thickness grafts are not susceptible to blister formation.

Human adipose tissue-derived cells delay re-epithelialization in comparison with skin fibroblasts in organotypic skin culture

BACKGROUND

Wound healing of deep and extensive burns can induce hypertrophic scar formation. During the early steps of wound healing fibroblasts migrate into the wounded area. Fibroblastic cells present in tissues other than dermis may also migrate into the wounded area and participate in the wound healing process.

OBJECTIVES

To examine the influence of human fibroblastic cells derived from subcutaneous fat or dermis on epidermal morphogenesis in vitro.

METHODS

We prepared human skin equivalents (HSEs) made of a collagen type I matrix populated either with dermal fibroblasts or adipose tissue-derived cells (ADCs), on top of which keratinocytes were seeded and subsequently grown at the air-liquid interface.

RESULTS

A fully differentiated epidermis was formed on matrices populated with ADCs. However, the HSE formed differed in a number of features from HSE generated with dermal fibroblasts. The major differences included: marked contraction of the dermal matrix, low lateral migration of keratinocytes, high keratin 17 expression indicating increased keratinocyte activation, delayed deposition of collagen IV at the epidermal/matrix junction, accumulation of alpha-smooth muscle actin-positive cells only underneath the epidermal compartment and positioning of these cells in a direction parallel to the epidermal compartment. The latter two phenomena have also been found in scar tissue.

CONCLUSIONS

The possibility of generating HSEs with different cell types represents an attractive approach for in vitro studies focusing on the mechanism of wound healing.

Scar assessment tools: implications for current research

Scarring is considered a major medical problem that leads to cosmetic and functional sequelae. Scar tissue is clinically distinguished from normal skin by an aberrant color, rough surface texture, increased thickness (hypertrophy), occurrence of contraction, and firmness. Marked histologic differences are the change in dermal architecture and the presence of cells such as the myofibroblast. Many assessment tools are available for analysis of pathologic conditions of the skin; however, there is no general agreement as to the most appropriate tools for evaluation of scar tissue. This review critically discusses currently available objective measurement tools, subjective assessment tools, and potential devices that may be available in the future for scar assessment.

Clinical and histopathological analysis of tissue retraction in tumescent liposuction assisted by external ultrasound

Multiple subjective evaluations and valuations in clinical studies have suggested that the use of external ultrasound in liposuction favors the degree of tissue retraction. However, studies do not exist that evaluate with objective parameters the degree of tissue retraction after liposuction assisted with external ultrasound. It is for this reason that a comparative clinical trial was carried out in 13 female patients to establish clinically and histopathologically the degree of tissue retraction that is produced after tumescent liposuction assisted by external ultrasound compared with the classic tumescent technique. All patients were tattooed in each hemiabdomen with reference points that formed a 7 x 7-cm square. Abdominal tumescent liposuction was carried out in all patients, with external ultrasound applied to the right hemiabdomen only, and without specifying to the patient the side on which the ultrasound was applied. The areas were measured and biopsies were acquired in each hemiabdomen 72 hours, 1 week, 2 weeks, 3 months, and 6 months postoperatively. The samples were evaluated by the same pathologist in a double-blind study. A survey of the patients was carried out regarding their appreciation of the results at the end of 3 months. On physical evaluation of the tattooed square, none of the thirteen patients presented significant differences in skin retraction (95% dependability by means of Student's t-test). The histological results showed that external ultrasound increased the degree of edema, vascular congestion, and inflammatory infiltration in the dermis during the first 3 months postoperatively. However, after 6 months no differences existed. Clinically, no patient observed a marked difference between the two hemiabdominal areas; an equal aesthetic result was obtained on both sides. In this clinical comparative trial, external ultrasound as a complementary method to tumescent liposuction did not increase the degree of tissue retraction after the liposuction, nor did it prove to be a determining factor in the immediate postoperative evolution.