Fibroblast subpopulations in intra-oral wound healing

Histological Examination of Lemongrass Resorbable Dressing on Gingival Healing after Gingivectomy in Rats

OBJECTIVES

 The present work aimed to evaluate the effect of lemongrass extract incorporated in a resorbable periodontal dressing on gingival wound healing microscopically, following gingivectomy in rats.

MATERIALS AND METHODS

 Thirty healthy adult male Sprague-Dawley rats were used in this study. Gingivectomy was performed on anterior area of lower jaw in the labial surface of central incisive and, subsequently, wound areas were covered with povidone iodine gel (group P, positive control, n = 10), lemongrass resorbable dressing (group L, n = 10), and a cellulose-based dressing containing myrrh (group M, positive control, n = 10). Histological changes were monitored in days 4, 7, and 14 postsurgery to evaluate fibroblast and collagen deposition as repair stage of healing process.

STATISTYCAL ANALYSIS

 One-way analysis of variance (ANOVA) followed by Tukey's post hoc for multiple comparisons were employed to measure differences between pairs of means, p-value of 0.05 was considered statistically significant.

RESULTS

 We observed significant difference repair parameters of the healing process between surgical sites treated with lemongrass periodontal dressing and control groups. Wounds treated with lemongrass dressing had greater fibroblast compared with control groups in 4 and 7 days after surgery (p ≤ 0.05).

CONCLUSION

 The results suggest positive potential therapeutic effects for this new formulation of periodontal dressing on acceleration of surgical wound healing that lead to improvement of periodontal treatment consequences following gingivectomy.

Enhancing the soft-tissue integration of dental implant abutments-in vitro study to reveal an optimized microgroove surface design to maximize spreading and alignment of human gingival fibroblasts

Within this work, we demonstrate the influences of different microgrooved surface topographies on the alignment and spreading of human gingival fibroblast (HGF) cells and present the optimal parameters for an improved soft-tissue integration design for dental implant abutments for the first time. Microgrooves with lateral widths from 2.5 to 75 μm were fabricated by UV-lithography and wet etching on bulk Ti6Al4V ELI material. The microstructured surfaces were compared to polished and ground surfaces as current state of the art. The resulting microtopographies were analyzed using vertical scanning interferometry and scanning electron microscopy. Samples loaded with HGF cells were incubated for 8 and 72 hr and cell orientation, spreading, resulting area, and relative gene expression were analyzed. The effect of contact guidance occurred on all microstructured surfaces yet there is a clear preferable range for the lateral widths of the microgrooves between approx. 11.5 and 13.9 μm and depths between 1.6 and 2.4 μm for an abutment surface design, where cell orientation and spreading maximizes. For structures larger than 30 μm, cell orientation, spreading and even gene expression of intercellular adhesion molecule-1 and yes-associated protein decrease.

Myofibroblasts in Palatal Wound Healing: Prospects for the Reduction of Wound Contraction after Cleft Palate Repair

The surgical closure of orofacial clefts is considered to impair maxillary growth and dento-alveolar development. Wound contraction and subsequent scar tissue formation, during healing of these surgical wounds, contribute largely to these growth disturbances. The potential to minimize wound contraction and subsequent scarring by clinical interventions depends on the surgeon’s knowledge of the events responsible for these phenomena. Fibroblasts initiate wound contraction, but proto-myofibroblasts and mature myofibroblasts are by far the most important cells in this process. Myofibroblasts are characterized by their cytoskeleton, which contains alpha-smooth-muscle actin. Additionally, their contractile apparatus contains bundles of actin microfilaments and associated contractile proteins, such as non-muscle myosin. This contractile apparatus is thought to be the major force-generating element involved in wound contraction. After closure of the wound, the myofibroblasts disappear by apoptosis, and a less cellular scar is formed. A reduction of contraction and scarring might be obtained by inhibition of myofibroblast differentiation, stimulation of their de-differentiation, stimulation of myofibroblast apoptosis, or impairment of myofibroblast function. In this review, we will discuss all of these possibilities, which ultimately may lead to a better outcome of cleft palate surgery.

Integrin α1β1

Integrin α1β1 is widely expressed in mesenchyme and the immune system, as well as a minority of epithelial tissues. Signaling through α1 contributes to the regulation of extracellular matrix composition, in addition to supplying in some tissues a proliferative and survival signal that appears to be unique among the collagen binding integrins. α1 provides a tissue retention function for cells of the immune system including monocytes and T cells, where it also contributes to their long-term survival, providing for peripheral T cell memory, and contributing to diseases of autoimmunity. The viability of α1 null mice, as well as the generation of therapeutic monoclonal antibodies against this molecule, have enabled studies of the role of α1 in a wide range of pathophysiological circumstances. The immune functions of α1 make it a rational therapeutic target.

Effect of transforming growth factor Beta 1 on wound healing in induced diabetic rats

OBJECTIVE

Delayed wound healing is one of the complications of diabetes mellitus, exhibited by profound inflammation and decreased granulation tissues. The current study was carried out to evaluate wound healing in both normal and diabetic rats. In addition, it evaluated the potential protective effect of transforming growth factor β1 (TGF β1), that has the broadest spectrum of actions, affecting all cell types that are involved in all stages of wound healing to accelerate wound healing in normal & diabetic rats.

METHODS

: The present study was performed on 40 male albino rats. Each 10 rats were designed as a group. Group I saved as control. They received incisional wound in their tongues 1 cm length and 1/2 cm depth. Group II received 500 ng/kg of TGF β1 5 minutes before wounding. Group III diabetes was induced then rats were treated as second group. At the 14(th) day post wounding, sections of tongues were taken for hematoxylin and eosin and Masson's trichome staining to examine the histological changes. The intracellular actions of TGF β1 were studied by TEM.

RESULTS

A higher cell proliferation rate and a denser and more organized new extracellular matrix and complete wound closure was detected at the 14(th) days in the TGF β1 treated wound in comparison with the 14(th) days for the untreated, control groups. There were delayed wound healing in diabetic rats, decreased re-epithelialization, granulation tissue thickness, matrix density, number of infiltrated cells, and number of capillaries. In TGF β1 treated diabetic rats, showed significant healing improvement was obvious as compared with diabetic rats.

CONCLUSIONS

A single intravenous injection of TGF β1 was sufficient to enhance wound healing in rat's tongue. This approach represents a new strategy that may be applied to the treatment of incisional wounds in human diabetic patients.

Isolation and characterization of chondroitin sulfates from sturgeon (Acipenser sinensis) and their effects on growth of fibroblasts

Chondroitin sulfate (CS) is a glycosaminoglycan that composed of hexosamine (D-galactosamine) and hexuronic acid (D-glucuronic acid) unit arranged in an alternating unbranched sequence. CS is an essential component of the extracellular matrix (ECM) of connective tissue. It is mainly covalently attached to core proteins in the form of proteoglycans so that it exhibits specific interactions with proteins for cell growth, differentiation, division and migration. In this study, CSs were purified from the cartilage and backbone of sturgeon (Acipenser sinensis). To characterize their biochemical properties, we performed disaccharide compositional analysis after chondroitinase ABC digestion, high performance size exclusion chromatography (HPSEC) and (1)H-NMR spectroscopy. We also investigated the effects of CSs on fibroblast proliferation and adhesion to determine whether wound healing was accelerated in vitro and proliferation of different mitogen-activated protein kinases (MAPK) signaling pathways was facilitated. The CS purified from sturgeon cartilage was primarily composed of 4-sulfated CS (88.8%) and sturgeon backbone CS contains more than 60% 6-sulfated CS. The average molecular weights of CSs obtained from sturgeon cartilage and backbone were found to be 8 and 43 kDa, respectively. Our results showed that both CSs are able to increase cell adhesion, induce proliferation and migration on fibroblasts and may accelerate wound healing by inducing MAPK signaling pathways.

Rheumatoid arthritis progression mediated by activated synovial fibroblasts

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovial hyperplasia and progressive joint destruction. Rheumatoid arthritis synovial fibroblasts (RASFs) are leading cells in joint erosion and contribute actively to inflammation. RASFs show an activated phenotype that is independent of the inflammatory environment and requires the combination of several factors. Although new aspects regarding RASF activation via matrix degradation products, epigenetic modifications, inflammatory factors, Toll-like receptor (TLR) activation and others have recently been uncovered, the primary pathophysiological processes in early arthritis leading to permanent activation are mostly unknown. Here, we review new findings regarding RASF activation and their altered behavior that contribute to matrix destruction and inflammation as well as their potential to spread RA.

Synovial fibroblasts spread rheumatoid arthritis to unaffected joints

Active rheumatoid arthritis originates from few joints but subsequently affects the majority of joints. Thus far, the pathways of the progression of the disease are largely unknown. As rheumatoid arthritis synovial fibroblasts (RASFs) which can be found in RA synovium are key players in joint destruction and are able to migrate in vitro, we evaluated the potential of RASFs to spread the disease in vivo. To simulate the primary joint of origin, we implanted healthy human cartilage together with RASFs subcutaneously into severe combined immunodeficient (SCID) mice. At the contralateral flank, we implanted healthy cartilage without cells. RASFs showed an active movement to the naive cartilage via the vasculature independent of the site of application of RASFs into the SCID mouse, leading to a marked destruction of the target cartilage. These findings support the hypothesis that the characteristic clinical phenomenon of destructive arthritis spreading between joints is mediated, at least in part, by the transmigration of activated RASFs.

Expression of proteins associated with cell-matrix adhesion in proliferative vitreoretinopathy designed by Dispase model

PURPOSE

During recent years, the interaction of cell surface molecule, extracellular matrix proteins, and cytoskeletal elements has been a topic for research for the purpose of understanding the mechanisms of pathologic conditions. This study aims to evaluate the expression of CD44, as a cell surface adhesion molecule; fibronectin (FN), as an extracellular and a cell surface protein; vinculin and actin/á-smooth muscle actin (alfa-SMA), as cytoskeletal elements; and the interactions of these proteins in the microenvironment of proliferative vitreoretinopathy (PVR).

METHODS

This experimental study was designed by the intravitreal Dispase model in rabbits and proteins' expression were evaluated via immunohistochemical staining.

RESULTS

As a cell surface protein, CD44 expression was determined in only four eyes focally and weakly, but in a small number of cells. Among the cytoskeletal proteins, vinculin expression was the most extensive and the strongest in intensity in epi- and subretinal membranes. Alpha-SMA expression was mostly present within small foci of cells. Fibronectin expression was determined in some of the eyes only faintly.

CONCLUSIONS

Vinculin seems to be involved in PVR pathogenesis. Variability in co-distribution of the expression of vinculin, FN, and alfa-SMA reflects the dynamic interactions evolving between cell and extracellular matrix during the epi- and subretinal membrane formations. The results of this study were determined not to be in support of the assumption that CD44 has a functional role in the pathogenesis of PVR.

Dynamic protein expression patterns during intraoral wound healing in the rat

Wound healing after cleft palate surgery is often associated with impairment of maxillary growth and dento-alveolar development. Wound contraction and scar tissue formation contribute strongly to these effects. In vitro studies have revealed that fibroblasts isolated during different phases of palatal wound healing show phenotypical differences. They change from a quiescent to an activated state and then partly back to a quiescent state. In this study, we evaluated the existence of fibroblast phenotypes at several time-points during palatal wound healing in the rat. Based on cytoskeletal changes (alpha-sma, vimentin, vinculin), integrin expression (alpha1, alpha2, alpha(v) and beta1) and changes in cellularity, we conclude that phenotypically different fibroblast populations are also present during in vivo wound healing. Alpha-sma and the integrin subunits alpha1 and alpha(v) were significantly up-regulated, and vinculin was significantly down-regulated, at early time-points compared to late time-points in wound healing. These changes point to an activated fibroblast state early in wound healing. Later in wound healing, these activated fibroblasts return only partially to the unwounded situation. These results strongly support the idea that different fibroblast populations with specific phenotypes occur in the course of palatal wound healing.

Matrix metalloproteinases and their tissue inhibitors in pressure-overloaded human myocardium during heart failure progression

OBJECTIVES

We studied the role of matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in fibrosis formation in the transition from hypertrophy to heart failure (HF) as well as the cellular source of MMPs and TIMPs.

BACKGROUND

Human pressure-overloaded hearts are characterized by a significant increase in cardiac fibrosis. However, the contribution of the proteolytic/antiproteolytic system in aortic stenosis (AS) during hypertrophy progression has not yet been elucidated.

METHODS

Three groups of AS patients (I: EF >50%, n = 12; II: EF 50% to 30%, n = 10; III: EF <30%, n = 12) undergoing aortic valve replacement and seven controls were studied. Tissue samples were investigated by immunoconfocal microscopy, Western blotting, and zymography.

RESULTS

Quantitative analysis by immunoconfocal microscopy and Western blotting showed an upregulation of MMP-1, -2, -3, -9, -13, and -14 in group I and further increases in later stages. Tissue inhibitors of metalloproteinase-1 and -2 were enhanced and TIMP-4 was decreased in comparison to control. Gelatinolytic activity of MMP-2 significantly (p < 0.05) increased 1.2-fold (group I), 1.5-fold (group II), and 1.6-fold (group III) over control. The level of collagen I was significantly upregulated in all AS groups. Immunoconfocal microscopy showed that MMPs and TIMPs are produced predominantly by fibroblasts. The number of proliferating fibroblasts was significantly elevated during the transition to HF (0.67 n/mm(2)-control, 5.03-group III, p < 0.05).

CONCLUSIONS

In human hearts a continuous turnover of the extracellular matrix occurs during the progression from compensated hypertrophy to HF that is characterized by the upregulation of MMPs and inadequate inhibition by TIMPs. The altered balance between proteolysis/antiproteolysis with accompanying proliferation of fibroblasts results in fibrosis progression.

The heme-heme oxygenase system: a molecular switch in wound healing

When cells are injured they release their contents, resulting in a local accumulation of free heme proteins and heme. Here, we investigated the involvement of heme and its degrading enzyme heme oxygenase (HO) in the inflammatory process during wound healing. We observed that heme directly accumulates at the edges of the wound after inflicting a wound in the palate of Wistar rats. This coincided with an increased adhesion molecule expression and the recruitment of leukocytes. To prove that heme is responsible for the recruitment of leukocytes, heme was administered intradermally 24 hours prior to injury. A clear heme-induced influx of both macrophages and granulocytes was observed. When examining the HO isoforms, HO-1 and HO-2, we found that HO-2 was present in the entire submucosa. Surprisingly, we observed also that HO-1 is significantly expressed in the epithelium of both the mucosa and the skin of animals without wounds. On inflammation, HO-1 expression increased, particularly in infiltrating cells during the resolution phase of inflammation. Interestingly, we observed that heme-induced influx of leukocytes was highly elevated after pharmacologic inhibition of HO activity. These observations suggest that the heme-HO system is closely involved in the control of wound healing. Our results demonstrate that the local release of heme may be a physiologic trigger to start inflammatory processes, whereas HO-1 antagonizes inflammation by attenuating adhesive interactions and cellular infiltration. Moreover, the basal level of HO expression in the skin may serve as a first protective environment against acute oxidative and inflammatory insults.