The change of break modulus drives human fibroblast differentiation in 3D collagen gels.

Extracellular matrix is one of the key environmental factors influencing cell survival and provides signals for cell morphological change, migration, proliferation and differentiation. However, the mechanism through which denatured collagen modulates the biological properties of fibroblasts, is unclear. We investigated the regulation of human fibroblast differentiation in vitro grown in collagen gels with different properties. The break modulus of collagen with denatured collagen and half-load normal collagen was reduced compared with that of normal collagen gel. Fibroblasts cultured in denatured collagen gels showed increased expression of matrix metalloproteinase9 ( MMP-9), tissue inhibitor of metalloproteinase 2 (TIMP2), α-smooth muscle actin (α-SMA), osteoblast cadherin, phosphorylated Myosin phosphatase target subunit1 (p-MYPT1), connective tissue growth factor, type I collagen, type III collagen, α-smooth muscle actin messenger RNA, RhoA, rho-associated protein kinase, and transforming growth factor ß receptors 1 and 2 compared with that in cells cultured in normal collagen gel. But there was no significant difference regarding expression level between denatured collagen gel and half-load normal collagen gel .These findings suggest that the change in break modulus caused by decreasing normal collagen concentration may be the key factor inducing fibroblast differentiation.

A severely infected diabetic foot treated successfully without using systemic antibiotics.

About 50% to 70% of all lower extremity amputations are related to diabetes infection. And antibiotic therapy is routinely used for all infected wounds to reduce the mortality of diabetic foot. Here, we report a case of diabetic foot with acute and deep severe infection. During hospital therapy, we used negative pressure therapy and extensive debridement without systemic antibiotic application, and we successfully rescued a foot from amputation. Negative pressure therapy and extensive debridement are very important and effective methods to control infection and promote wound healing in diabetes foot.

[Exploring the three-dimensional structure of dermal tissues of normal skin and scar in rat with synchrotron radiation X-ray imaging technology].

OBJECTIVE: To compare the morphological difference between dermal tissue of normal skin and that of scar in rat, and to explore its structural pattern. METHODS: The full-thickness skin and the scar tissue formed 3 weeks after wound healing from SD rats were harvested as samples, which were prepared appropriately afterwards. Samples were scanned and imaged with synchrotron radiation technology, micro-CT, and phase-contrast imaging technology. The images were rebuilt with three-dimensional software. RESULTS: The micro-CT was materialized by using X-ray generated by synchrotron radiation light source. The structure of dermal tissues was clearly shown with the assistance of phase-contrast imaging technology in the process. It was demonstrated that the dermal tissues of normal skin of rat were mainly composed of collagenous fibers, which twined together to form an olive-like structure. These olive-like structures as basic units were arranged randomly in a certain way. The collagenous fibers in dermal tissue of the scar were arranged in a parallel manner, while some fibers were crooked and arranged in a disorderly manner. CONCLUSIONS: Dermal tissue of normal skin in rat has stable three-dimensional structure, and its basic structure and manner of composition are obviously different from those of scar dermal tissue.

[Advances in research of the mechanism of "covert disorder" in diabetic skin].

The diabetic ulceration is not uncommon, and becomes refractory, as the skin in a diabetic patient is relatively thin as well as hypoesthetic and less sensitive to temperature. As there are already preexisting histological and cellular derangement in the skin, healing of the skin injury is difficult, thus resulting in an intractable ulceration. When diabetes is not controlled, the skin contents of sugar and advanced glycation end product accumulate, invoking cellular deformation and accumulation of matrix metalloproteinases (MMP), resulting in an imbalance between MMP and its inhibitors, malfunction of growth factors, and inflammatory reaction. These processes lead to obvious skin thinning, denaturation of connective tissues, thickening of vascular basal membrane, and neuropathy, etc. These pathological alterations could be recognized as "covert disorder" of skin in diabetic patients and may be underlying disorders in producing indolent diabetic ulcers.

[Exploratory study on the micro-remodeling of dermal tissue].

OBJECTIVE: To explore the effect of three-dimensional structure of dermal matrix on biological behavior of fibroblasts (Fb) in the microcosmic perspective. METHODS: The three-dimensional structure of dermal tissue was analyzed by plane geometric and trigonometric function. Microdots structure array with cell adhesion effect was designed by computer-assisted design software according to the adhesive and non-adhesive components of dermal tissue. Four sizes (8 microm x 3 microm, space 6 microm; 16 microm x 3 microm, space 6 microm; 16 microm x 5 microm, space 8 microm; 20 microm x 3 microm, space 2 microm) of micropier grid used for cell culture (MPGCC) with cell-adhesive microdots, built up with micro-pattern printing and molecule self-assembly method were used to culture dermal Fb. Fb cultured with cell culture matrix without micropier grid was set up as control. The expression of skeleton protein (alpha-SMA) of Fb, cell viability and cell secretion were detected with immunohistochemistry, fluorescent immunohistochemistry, MTT test and the hydroxyproline content assay. RESULTS: The three-dimensional structure of dermal tissue could be simulated by MPGCC as shown in arithmetic analysis. Compared with those of control group [(12 +/- 3)% and (0.53 +/- 0.03) microg/mg, (0.35 +/- 0.04)], the expression of alpha-SMA [(49 +/- 3)%, (61 +/- 3)%, (47 +/- 4)%, (51 +/- 3)%] and the content of hydroxyproline [(0.95 +/- 0.04), (0.87 +/- 0.03), (0.81 +/- 0.03), (0.77 +/- 0.03) microg/mg] were increased significantly (P < 0.05), the cell viability of Fb (0.12 +/- 0.03, 0.13 +/- 0.04, 0.14 +/- 0.03, 0.19 +/- 0.03) cultured in MPGCC was decreased significantly (P < 0.05). When the parameters of micropier grid were changed, the expression of alpha-SMA, the cell viability and the content of hydroxyproline of Fb cultured in four sizes of MPGCC were also significantly changed as compared with one another (P < 0.05). CONCLUSIONS: MPGCC may be the basic functional unit of dermal template, or unit of dermal template to call. Different three-dimensional circumstances for dermal tissue can result in different template effect and wound healing condition.

[The effect of focal-adhesion micromanipulation in trauma and wound healing].

OBJECTIVE: To explore the effect of focal-adhesion micromanipulation on the biological behavior of fibroblast. METHODS: Micro-pot was made by microcontact printing. The molecules of constitutive protein was adhered on micro-pot by self-assemble of peptides. Skin fibroblasts were cultured on the membrane by self-made biomechanical cell culture for 2 weeks. Morphology observation and cell immunohistochemistry analysis was performed. RESULTS: After 2 weeks, the morphology of the fibroblasts was diverse and more compliant. Cell immunohistochemistry analysis found that the expression of integrinbeta1, alpha5 and tensin was dramatically reduced. CONCLUSIONS: The morphology and the biological behaviour of the fibroblasts in hypertrophic scar can be changed after micromanipulation of focal adhesion.

Antimitotic drug injections and radiotherapy: a review of the effectiveness of treatment for hypertrophic scars and keloids.

Scars are a common complication of surgery or burn wound management. Scars occur over the body, affecting people of both sexes and all ages. Scar therapy is a constant clinical challenge; antimitotic drugs and radiotherapy are used with varying degrees of success. This article examines the success of both these types of treatment modalities.

[Discoidin domain receptors (DDRs) expression in pathological scar fibroblast formation].

OBJECTIVE: To explore the role of discoidin domain receptors (DDRs) in the formation of the keloid. METHODS: The real-time quantitative PCR was used to compare the DDRs expression in the keloids and normal fibroblasts. RESULTS: The level of DDR1 expression was significantly higher in keloid than in normal fibroblast (20.98 vs 4.2, P <0.01; 7.9 vs 4.23, P <0.05). The level of DDR1 expression in keloid was also higher significantly than that in hypertropic scar (20.98 vs 7.9, P < 0.01). However, the level of DDR2 expression was somewhat higher in keloid than in normal fibroblasts, the difference seemed not to be significantly in probability (358, 332 vs 278, P > 0.05). CONCLUSIONS: DDRs may exert effect on keloid cell behaviours.