Proliferation Of Connective Tissue Cells Research Articles

Analysis and Identification of Methylation‐Modifying Genes Associated with Hypoxia and Immunity in Keloids

Background. Keloids are benign fibroproliferative tumors that are unique to humans. However, the exact mechanism of keloid formation remains unclear. The inflammatory cytokines released by immune cells can activate fibroblasts, connective tissue cell proliferation, and angiogenesis. Hypoxia is common in the process of fibrosis in many diseases. This study aimed to investigate the relationship between immune response, hypoxia, and keloid formation. Methods. Gene methylation and expression data were downloaded from the GEO database. Thereafter, differentially methylated genes associated with immunity and hypoxia were identified. Machine learning was performed to identify potential diagnostic/immunity/hypoxia‐related differentially methylated/expressed genes, followed by analysis of functional enrichment, transcription factors, protein‐protein interactions, and expression validation by reverse transcription quantitative polymerase chain reaction and immunohistochemistry. Results. In total, 16 immunity/hypoxia‐related hypermethylated low‐expression genes and 18 immunity/hypoxia‐related hypomethylated high‐expression genes were identified in keloids. Based on machine learning, nine differentially methylated and expressed genes were selected as potential diagnostic markers for keloids, including two hypoxia‐related genes (CDKN1A and PGAM2) and seven immunity‐related genes (DCD, PTGDS, WFIKKN1, SEMA5A, IL1R1, ITGAL, and SOS1). Some significantly enriched signaling pathways were identified, including the FoxO, PI3K‐Akt, focal adhesion, and ErbB signaling pathways. SOS1 is involved in disease regulation with 65 transcription factors and has a higher interaction score with other molecules. Conclusions. Two hypoxia‐related genes (CDKN1A and PGAM2) and seven immunity‐related genes (DCD, PTGDS, WFIKKN1, SEMA5A, IL1R1, ITGAL, and SOS1) could be considered potential diagnostic markers for keloids, and may be helpful in understanding the importance of oxygen balance and immune regulation in keloids.

Therapy of pathological scars.

A scar develops following the appearance of a deep tissue defect as part of the physiological wound healing process. The initial inflammatory response is followed by proliferation of connective tissue cells, which form fibrosis as a final tissue substitute. Disorders can occur at all stages of the process and are most commonly manifested as impaired wound healing or the formation of atrophic and hypertrophic scars or keloids. The focus of this article is on the treatment of pathologic scars, which are an indication for therapy due to functional limitations, complaints, and stigmatization, among other reasons. Conservative medical, physical, surgical and laser therapeutic approaches are pursued. The basis for this is an understanding of the pathophysiological mechanisms and factors influencing the choice of therapy, as well as an interdisciplinary and interprofessional therapeutic approach.

Prolonged Effect of Seminal Plasma on Global Gene Expression in Porcine Endometrium.

Seminal plasma (SP) deposited in the porcine uterine tract at the time of mating is known to elicit an initial response that is beneficial for pregnancy outcome. However, whether SP has any long-term effect on alterations in endometrial molecular and cellular processes is not known. In this study, using microarray analyses, differential changes in endometrial transcriptome were evaluated after Day 6 of SP-infusion (6DPI) or Day 6 of pregnancy as compared to corresponding day of estrous cycle. Both, pregnancy and SP induced significant changes in the endometrial transcriptome and most of these changes were specific for a particular group. Functional analysis of differentially expressed genes (DEGs) using Ingenuity Pathway Analysis revealed that inhibition in immune response was affected by both pregnancy and SP infusion. Long-term effects of SP included differential expression of genes involved in inhibition of apoptosis, production of reactive oxygen species and steroid biosynthesis, and activation of processes such as proliferation of connective tissue cells and microvascular endothelial cells. Moreover, interleukin-2 and interferon-γ was identified to be responsible for regulating expression of many DEGs identified on 6DPI. The present study provides evidence for the long-term effects of SP on porcine endometrium that can be beneficial for pregnancy success.

Histological Investigations for Cordia Myxa During the Treatment of Gastritis in Local Rabbits

Background: The goal of this study was to evaluate the effect of medical fruits, through H+ proton pump inhibitors and observation to main of histological changes accompanying for treatment. Methods, Adult domestic healthy rabbits, all experimental animals were adapted in animal house. Animals were taken for this study distributed into three group, control (5 ml/kg b.w) gastritis (10% glacial acetic acid 1ml//kg b.w) and treatment group (5 ml/kg b.w) oral administration during 21 day for 3 time daily. Results: the main histological observations for effects of (Juicer fruit Bumper) during induce inflammation by 10% acetic acid, after 4hr showing the inflammation region in internal surface in fundic region but most of internal surface it’s normally. Histologically, the stomach of gastritis group was observed the erosion in epithelia surface and congestion of blood vessels, gastric pits disappear but most of changes which accrue in lamina propria generally. The rabbits of treated group was observed reductions in inflammatory area, with some extent of mucosal regeneration (re-epithelization) and the parietal cells appeared a granular cytoplasm and proliferation of connective tissue cells (granulation tissue). Conclusions: these findings suggest that (Cordia myxa) considered perfect anti-inflammatory and H+ proton inhibited pump

Complement C1r serine protease contributes to kidney fibrosis.

We have previously reported that complement activation precedes the development of kidney fibrosis; however, little is known about the cellular mechanisms involved in this transition. We hypothesized that increased expression of C1 complex protease C1r, the initiator of complement activation, contributes to tubulointerstitial fibrosis and tested this idea in mice with global deletion of C1r. Although expression of C1r in untreated wild-type (WT) mice was higher in the liver compared with kidney tissue, administration of folic acid (FA) led to upregulation of C1r mRNA and protein levels only in kidney tissue. Immunohistochemistry and in situ hybridization experiments localized increased expression of C1r and C1s proteases to renal tubular epithelial cells. C1r-null mice had reduced acute tubular injury and inflammation measured 2 days after FA administration compared with WT mice. C1r deletion reduced expression of C1s, C3 fragment formation, and organ fibrosis measured 14 days after FA administration. Differential gene expression performed in kidney tissue demonstrated that C1r-null mice had reduced expression of genes associated with the acute phase response, complement, proliferation of connective tissue cells (e.g., platelet-derived growth factor receptor-β), and reduced expression of genes associated with inflammation compared with FA-treated WT mice. In vitro experiments in renal epithelial cells demonstrated that C1s expression is dependent on increased C1r expression and that interferon-γ induces the expression of these two proteases. We conclude that increased expression of C1 complex proteases is associated with increased tissue inflammation and complement C3 formation and represents an important pathogenic mechanism leading to FA-mediated tubulointerstitial fibrosis.

In Vivo Remodeling of an Extracellular Matrix Cardiac Patch in an Ovine Model.

Lack of an ideal patch material for cardiac repairs continues to challenge congenital heart surgeons. The current materials are unable to grow and result in scarring, contraction, and arrhythmias. An acellular extracellular matrix (ECM) patch derived from porcine small intestinal submucosa has demonstrated remodeling potential when used to repair various tissues. This study investigated the in vivo electrophysiologic, mechanical, and histological properties of an ECM patch used to repair a right-ventricular (RV) wall defect in a growing ovine model. A full-thickness, 2 × 2 cm RV defect was created in 11 juvenile sheep and repaired with an ECM patch. Longitudinal RV three-dimensional-electrical mapping, magnetic resonance imaging (MRI), and histological analysis were performed at 3, 6, 9, and 12 months. Three-dimensional mapping demonstrated consistent conduction across the patch with little to no difference in voltage, but conduction velocity was consistently less than native myocardium. Magnetic resonance imaging revealed changing strain properties of the patch which by 9-12 months resembled native tissue. Histologic analysis at 3 months demonstrates cardiomyocyte degeneration and partial replacement via proliferation of connective tissue cells that were predominately fibroblasts and smooth muscle cells. There was marked neovascularization and an absence of calcification at 12 months. Over time, the ECM patch remained viable with stable muscle at the edges. In growing sheep, an ECM patch becomes a viable tissue and remains so up to at least a year. Although ECM demonstrates some functional aspects of remodeling to native myocardium, histologically it remained immature.

Functionalization of hyaluronic acid hydrogels with ECM-derived peptides to control myoblast behavior

Volumetric muscle loss (VML) occurs when skeletal muscle injury is too large for the body to fully self-repair. Typically, fibrotic tissue fills the void, which reduces muscle functionality and limb movement. Although a wide variety of natural and synthetic scaffolds have been studied with the purpose of providing the appropriate structural support, to date no scaffold has significantly restored muscle functionality after VML. Satellite cells, adult stem cells within the muscle capable of restoring smaller injuries, are sensitive to the stiffness and composition of the surrounding environment. Scaffolds that only address structural support are not sufficient to restore functionality and instead need to be designed to both promote satellite cell activation and prevent excessive fibroblast recruitment. The objective of this study was to design a scaffold that mimicked the regenerative environment and determine how the biomechanical properties differentially influence myogenic precursor and connective tissue cells. One of the main extracellular matrix (ECM) molecules upregulated during regeneration is hyaluronic acid (HA). Therefore, thiol-modified HA and poly(ethylene glycol) diacrylate hydrogels were generated and functionalized with peptides based on ECM known to influence regeneration, including fibronectin, laminin and tenascin-C. Scaffolds with different stiffness were created by varying HA content. The influence of HA stiffness and peptide functionalization on myogenic precursor and connective tissue cell proliferation, migration and gene expression was quantified. Our results indicated that HA hydrogels functionalized with the laminin peptide, IKVAV, show potential due to the enhanced promotion of myogenic cell behaviors including migration, proliferation and an increase in relevant transcription factors. Statement of SignificanceThe goal of this study was to identify hyaluronic acid (HA) hydrogels with peptide and stiffness combinations that will direct muscle-derived cells towards regenerating phenotypes. While the interaction of skeletal muscle with RGD-functionalized HA hydrogels has been investigated, none of the other peptides described in this study had been used in the context of HA-based scaffolds and skeletal muscle-derived cells. Notably, the response of cells to variations in mechanics was dependent on ECM coating and lineage. The 3% HA functionalized with the laminin peptide, IKVAV, showed the most promise for future in vivo studies, as these hydrogels best promoted myoblast cell proliferation, attachment and spreading, enhanced migration over connective tissue cells and upregulated transcription factors associated with activated satellite cells.

Hyaluronic acid, CD44 and RHAMM regulate myoblast behavior during embryogenesis

Hyaluronic acid (HA) is an extracellular matrix (ECM) component that has been shown to play a significant role in regulating muscle cell behavior during repair and regeneration. For instance, ECM remodeling after muscle injury involves an upregulation in HA expression that is coupled with skeletal muscle precursor cell recruitment. However, little is known about the role of HA during skeletal muscle development. To gain insight into the way in which HA mediates embryonic myogenesis, we first determined the spatial distribution and gene expression of CD44, RHAMM and other HA related proteins in embryonic day (E)10.5 to E12.5 murine forelimbs. While HA and CD44 expression remained high, RHAMM decreased at both the protein (via immunohistochemistry) and RNA (via qPCR) levels. Next, we determined that 4-methylumbelliferone-mediated knockdown of HA synthesis inhibited the migration and proliferation of E11.5/E12.5 forelimb-derived cells. Then, the influence of CD44 and RHAMM on myoblast and connective tissue cell behavior was investigated using antibodies against these receptors. Anti-RHAMM, but not anti-CD44, significantly decreased the total distance myogenic progenitors migrated over 24 h, whereas both inhibited connective tissue cell migration. In contrast, anti-CD44 inhibited the proliferation of connective tissue cells and muscle progenitors, but anti-RHAMM had no effect. However, when myoblasts and connective tissue cells were depleted of CD44 and RHAMM by shRNA, motility and proliferation were significantly inhibited in both cells indicating that blocking cell surface-localized CD44 and RHAMM does not have as pronounced effect as global shRNA-mediated depletion of these receptors. These results show, for the first time, the distribution and activity of RHAMM in the context of skeletal muscle. Furthermore, our data indicate that HA, through interactions with CD44 and RHAMM, promotes myogenic progenitor migration and proliferation. Confirmation of the role of HA and its receptors in directing myogenesis will be useful for the design of regenerative therapies that aim to promote the restoration of damaged or diseased muscle.

Immunobiological and morphofunctional indicators with dysbacteriosis of the intestine of rabbits

The article presents results of research of dynamics of morphological, biochemical, haematological and immunological parameters when changing the quantity and species of microorganisms of intestinal microbiocenosis of the rabbits. With the dominance of pathogenic bacteria in rabbit intestinal microbiocenoses, the titer of bifidumbacteria was 10-5-10-4, a decrease in the number of lactobacilli, an increase in the number of enterobacteria, a correlation between the colonization index and the degree of adhesion of bacteria was revealed; an increase in the total number of leukocytes, lymphocytes, erythrocytes, hematocrit, alanine aminotransferase level, aspartate aminotransferase, lactate dehydrogenase, total bilirubin, -amylase, albumin, alkaline phosphatase, T-killer level, NK cells, concentration of C-reactive protein. We observed a decrease in the concentration of hemoglobin, monocytes, total protein level, T-lymphocytes, T-helpers, B-lymphocytes, phagocytic index, phagocytic activity of leukocytes, NST-spontaneous, NST-stimulated. Dynamics of morphological indicators was characterized by a disorder of the circulation of organs, a predominance of dystrophic and necrotic processes in the tissues and organs of the cardiovascular, respiratory, digestive, excretory system. Infiltration with mononuclear and segmented leukocytes was noted, diffuse lymphoid proliferation of the mucous membranes of the organs, hyperemia, edema, multiple hemorrhages, accumulation of hemorrhagic exudate in the lumen of the respiratory, digestive and urogenital tracts. Observed catarrhal-hemorrhagic inflammation of the gastrointestinal tract; mucous membrane of the stomach, small and large intestines edematic, hyperemic, with hemorrhages, covered with mucus, fibrinous films, with necrotic areas. The signs of acute diffuse interstitial nephritis, characterized by proliferation of connective tissue cells with a predominance of lipoblast and epithelioid cells, are revealed. In the presence of bacterial cells in the lumen of the tubules, the parenchyma of the cortical and medullar layers was marked by microabscesses. Accidental transformation of the thymus was observed, characterized by signs of a circulatory disorder, a decrease in the area of the cortex, the formation of cysts; signs of diffuse hyperplasia of the spleen with necrobiotic changes in the foci of proliferation, reduction of the area of lymphoid follicles, expansion of the area occupied by the red pulp of follicles, hyperplasia of follicles of white pulp with foci of necrosis. Identified multiple bacterial embolism of blood vessels, developed signs of hemorrhagic Diathesis, watched the development of sign infiltrative itch processes.

Expansion of specialized epidermis induced by hormonal state and mechanical strain

In mammals, some sites of specialized skin such as the palms, soles, and lips grow proportionally with the animal. However, other types of specialized skin such as the nipple and anal/genital region are dramatically altered with changes of reproductive status. The specific cell types that mediate the growth of these sites have not been identified. In the mouse, we observed a dramatic expansion of the specialized epidermis of the nipple, coupled to changes in connective tissue and hair shaft density, which we designate as areola formation. During this process thymidine analog uptake was elevated in the epidermis and hair follicles. Although there were no changes in connective tissue cell proliferation, we did observe an altered expression of extracellular matrix genes. In addition, the fibroblasts of the virgin nipple areola and region showed increased transcript and protein levels for estrogen, progesterone, relaxin, and oxytocin relative to those of ventral skin. To determine the role of pregnancy, lactation hormonal milieu, and localized mechanical strain on areola formation, we created models that separated these stimuli and evaluated changes in gross structure, proliferation and protein expression. While modest increases of epidermal proliferation and remodeling of connective tissue occurred as a result of individual stimuli, areola formation required exposure to pregnancy hormones, as well as mechanical strain.

Potential Regulatory Role of MicroRNAs in the Development of Bovine Gastrointestinal Tract during Early Life

This study aimed to investigate the potential regulatory role of miRNAs in the development of gastrointestinal tract (GIT) during the early life of dairy calves. Rumen and small intestinal (mid-jejunum and ileum) tissue samples were collected from newborn (30 min after birth; n = 3), 7-day-old (n = 6), 21-day-old (n = 6), and 42-day-old (n = 6) dairy calves. The miRNA profiling was performed using Illumina RNA-sequencing and the temporal and regional differentially expressed miRNAs were further validated using qRT-PCR. Analysis of 16S rRNA gene copy numbers was used to quantify total bacteria, Bifidobacterium and Lactobacillus species. The expression of miR-143 was abundant in all three gut regions, at all time points and it targets genes involved primarily in the proliferation of connective tissue cells and muscle cells, suggesting a role in regulating rapid tissue development during the early life of calves. The expression of miR-146, miR-191, miR-33, miR-7, miR-99/100, miR-486, miR-145, miR-196 and miR-211 displayed significant temporal differences (FDR <0.05), while miR-192/215, miR-194, miR-196, miR-205 and miR-31 revealed significant regional differences (FDR <0.05). The expression levels of miR-15/16, miR-29 and miR-196 were positively correlated with the copy numbers of 16S rRNA gene of Bifidobacterium or Lactobacillus species or both (P<0.05). Functional analysis using Ingenuity Pathway Analysis identified the above mentioned differentially expressed miRNAs as potential regulators of gut tissue cell proliferation and differentiation. The bacterial density-associated miRNAs were identified as modulators of the development of lymphoid tissues (miR-196), maturation of dendritic cells (miR-29) and development of immune cells (miR-15/16). The present study revealed temporal and regional changes in miRNA expression and a correlation between miRNA expression and microbial population in the GIT during the early life, which provides further evidence for another mechanism by which host-microbial interactions play a role in regulating gut development.

Inhibition of fibroblast adhesion by covalently immobilized protein repellent polymer coatings studied by single cell force spectroscopy

Cochlea implants (CI) restore the hearing in patients with sensorineural hearing loss by electrical stimulation of the auditory nerve via an electrode array. The increase of the impedance at the electrode-tissue interface due to a postoperative connective tissue encapsulation leads to higher power consumption of the implants. Therefore, reduced adhesion and proliferation of connective tissue cells around the CI electrode array is of great clinical interest. The adhesion of cells to substrate surfaces is mediated by extracellular matrix (ECM) proteins. Protein repellent polymers (PRP) are able to inhibit unspecific protein adsorption. Thus, a reduction of cell adhesion might be achieved by coating the electrode carriers with PRPs. The aim of this study was to investigate the effects of two different PRPs, poly(dimethylacrylamide) (PDMAA) and poly(2-ethyloxazoline) (PEtOx), on the strength and the temporal dynamics of the initial adhesion of fibroblasts. Polymers were immobilized onto glass plates by a photochemical grafting onto method. Water contact angle measurements proved hydrophilic surface properties of both PDMAA and PEtOx (45 ± 1° and 44 ± 1°, respectively). The adhesion strength of NIH3T3 fibroblasts after 5, 30, and 180 s of interaction with surfaces was investigated by using single cell force spectroscopy. In comparison to glass surfaces, both polymers reduced the adhesion of fibroblasts significantly at all different interaction times and lower dynamic rates of adhesion were observed. Thus, both PDMAA and PEtOx represented antiadhesive properties and can be used as implant coatings to reduce the unspecific ECM-mediated adhesion of fibroblasts to surfaces.

Mesenteric ischemia–reperfusion injury: Specific impact on different cell populations within the jejunal wall in rats

The progress of jejunal damage and recovery in the course of mesenteric ischemia–reperfusion injury in rats at different time periods was investigated. Mesenteric ischemia lasting 1h followed by 1h of reperfusion caused a significant disintegration of the mucosa, reduction of the muscular layer and diminution of the wall thickness. The loss of epithelium included enterocytes, goblet cells and Paneth cells. Paradoxically, increasing numbers of serotonin-producing cells and the beginning of regenerative processes, expressed by significantly higher proliferation, were recorded in the epithelium during this period. Disintegration of connective tissue and massive degranulation of serotonin-positive cells were found in the lamina propria. After 24h of reperfusion, restitution of the mucosa was found, expressed by normal villous morphology and re-epithelialization. However, some parameters were still significantly affected even more than in the acute phase of reperfusion. In the epithelium, decreased numbers of Paneth cells and increased population of serotonin-producing cells were found. The greatest proliferation of connective tissue cells and intensified reduction of the muscular layer were also detected in this reperfusion period. After 30 days of reperfusion, moderate damage remained, but only the increased number of Paneth cells and decreased number of serotonin-producing cells in the lamina propria were significant.

β‐1 and β‐2, but not α‐1 and α‐2, adrenoceptor blockade delays rat cutaneous wound healing

The sympathetic nervous system plays an important role in wound healing, but its mechanism of action is poorly understood. The aim of this study was to investigate the effects of beta- and alpha-adrenoceptor blockade on cutaneous wound healing. Male rats were treated with propranolol (beta1- and beta2-antagonist), atenolol (beta1-antagonist), or phentolamine (alpha1- and alpha2-antagonist) dissolved in drinking water. A full-thickness excisional lesion was created and the wound area was measured. Fourteen days after wounding, lesions and adjacent skin were removed, formalin-fixed, and paraffin-embedded. Sections were stained with hematoxylin-eosin and toluidine blue, and immunostained for alpha-smooth muscle actin and proliferating cell nuclear antigen. Wound contraction was delayed in propranolol- and atenolol-treated animals but not in phentolamine-treated animals. Reepithelialization was decreased only in propranolol-treated animals. beta1- and beta2-adrenoceptor blockade delayed leukocyte migration, epidermal and connective tissue cell proliferation, myofibroblastic differentiation, and mast cell migration. The volume density of blood vessels was increased in the propranolol- and atenolol-treated animals compared with controls. The levels of matrix metalloproteases (MMP-2 and MMP-9) decreased in the propranolol- and atenolol-treated animals. alpha1- and alpha2-adrenoceptor blockade only affected leukocyte migration, epithelial and connective tissue cell proliferation, and pro-MMP-9 levels. In conclusion, beta-1 and beta-2, but not alpha-1 and alpha-2, adrenoceptor blockade delays cutaneous wound healing.

Negative and Positive Regulation of MAPK Phosphatase 3 Controls Platelet-derived Growth Factor-induced Erk Activation

MAPK phosphatases (MKPs) are dual specificity phosphatases that dephosphorylate and thereby inactivate MAPKs. In the present study, we provide evidence that platelet-derived growth factor BB (PDGF-BB) regulates MKP3 (DUSP6), which is considered to be a phosphatase highly selective for Erk. Intriguingly, we observed that Mek is positively regulated by MKP3, whereas Erk itself is negatively regulated. In addition, we found that activation of PDGF receptor alpha or beta leads to a rapid proteasomal degradation of MKP3 in a manner that requires Mek activation; this feed-forward mechanism was found to be essential for efficient Erk phosphorylation. We could also demonstrate that PDGF-BB stimulation induces phosphorylation of MKP3 at Ser-174 and Ser-300; phosphorylation of Ser-174 is involved in PDGF-induced MKP3 degradation, since mutation of this site stabilized MKP3. Moreover, activated Erk induces mkp3 expression, leading to restoration of MKP3 levels after 1-2 h and a concomitant dephosphorylation of Erk in cells with activated PDGFRalpha. Reducing the MKP3 level by small interfering RNA leads to an increased Erk activation and mitogenic response to PDGF-BB. In conclusion, MKP3 is an important regulator of PDGF-induced Erk phosphorylation acting in both a rapid positive feed-forward and a later negative feed-back loop.

20-HETE inhibits the proliferation of vascular smooth muscle cells via transforming growth factor-β

20-Hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P450 arachidonic acid metabolite, has been shown to modulate the growth of vascular smooth muscle cells (VSMCs). We asked whether 20-HETE modulates the proliferation of R22D cells, a clonal VSMC from neonatal rats, by releasing transforming growth factor-beta (TGF-beta). Incubation of R22D cells with 20-HETE for 24 h attenuated [(3)H]thymidine incorporation in a concentration-dependent manner without causing the release of lactate dehydrogenase. 20-HETE also inhibited platelet-derived growth factor (PDGF)-induced [(3)H]thymidine incorporation in R22D cells and human VSMCs. At 5 muM, 20-HETE reduced [(3)H]thymidine incorporation by 34 +/- 6%; anti-TGF-beta neutralizing antibody, but not nonspecific IgG, completely reversed the attenuated [(3)H]thymidine incorporation induced by 20-HETE. In addition, 20-HETE attenuated fetal bovine serum- and PDGF-induced expression of cyclin D1, a downstream effector of TGF-beta(1), which was reversed by anti-TGF-beta antibody. Further studies demonstrated that 20-HETE may increase TGF-beta release to a level high enough to inhibit [(3)H]thymidine incorporation without altering the steady-state mRNA level of TGF-beta. Nevertheless, pretreatment of indomethacin (a cyclooxygenase inhibitor) or paxilline (a potassium channel inhibitor) did not affect the inhibitory effect on DNA synthesis induced by 20-HETE. These results demonstrate for the first time a growth-inhibitory effect induced by 20-HETE, which may be mediated by TGF-beta.

Overweight induced by high-fat diet delays rat cutaneous wound healing

Prolonged wound healing is a complication that contributes to morbidity and mortality. Overweight people regularly undergo surgery and trauma, and often develop chronic wounds, but the effects of the adipose tissue excess on cutaneous wound healing are not well understood. This study tested the hypothesis that overweight induced by a high-fat diet impairs rat cutaneous wound healing. Male Wistar rats were fed with either a high-fat or a standard (control) diet. After 15 weeks, an excisional lesion was done and the animals were killed 21 d later. Wound contraction and re-epithelialization, blood pressure, glucose and retroperitoneal fat were evaluated. After killing, lesion and adjacent normal skin were formol-fixed and paraffin-embedded. Inflammatory infiltrate, myofibroblasts, collagen fibres and cellular proliferation were analysed and blood vessels were evaluated using stereological methods. There was no difference in blood pressure and glucose, but retroperitoneal fat increased in the high-fat diet group. Animals fed with the high-fat diet presented delayed wound contraction and re-epithelialization. It was found that 21 d after wounding, overweight induced by a high-fat diet increased the inflammatory infiltrate and delayed myofibroblastic differentiation, collagen deposition, epithelial and connective tissue cell proliferation, and angiogenesis. These findings support the hypothesis that a high-fat diet exerts negative effects on rat cutaneous wound healing, due mainly to the prolongation of the inflammatory phase.

BLOCKADE OF β1‐ AND β2‐ADRENOCEPTORS DELAYS WOUND CONTRACTION AND RE‐EPITHELIALIZATION IN RATS

1. The participation of sympathetic efferent fibres in wound healing is not well understood. The aim of the present study was to investigate the effects of beta(1)- and beta(2)-adrenoceptor blockade on rat excisional cutaneous wound healing. 2. Male rats were treated orally with propranolol dissolved in drinking water (50 mg/kg per day), whereas the control group received drinking water without propranolol. Propranolol was administered daily until rats were killed. A full-thickness excisional lesion was performed. The lesion area was measured to evaluate wound contraction. After rats had been killed, lesion and adjacent normal skin were formol fixed and paraffin embedded. Sections were stained with haematoxylin-eosin, Sirius red or Toluidine blue and immunostained for a-smooth muscle actin or proliferating cell nuclear antigen. 3. Propranolol-treated rats presented delayed wound contraction and epidermal healing and decreased hydroxyproline levels, collagen density and neo-epidermis thickness. Blockade of beta(1)- and beta(2)-adrenoceptors increased epidermal and connective tissue cell proliferation, polymorphonuclear leucocyte migration, myofibroblast density and mast cell migration. The volume density of blood vessels was increased and vessels were more dilated in propranolol-treated animals. 4. Thus, we conclude that beta(1)- and beta(2)-adrenoceptor blockade impairs cutaneous wound healing. This information should be considered by physicians during the treatment of patients who present with hypertension and problems in the healing process (such as venous ulcers).

Connective tissue growth factor expression is decreased in acute ascending aortic dissections and increased in degenerative ascending aortic aneurysms

Purpose. Both aortic aneurysms and aortic dissections exhibit abnormal extracellular matrix properties. Connective tissue growth factor (CTGF) can induce connective tissue cell proliferation and extracellular matrix synthesis. The role of CTGF in thoracic aortic disease has never been investigated. We sought to compare the expression of CTGF in degenerative ascending aortic aneurysms and ascending aortic dissection. Methods. Intraoperative samples of ascending aorta were obtained from 47 patients: 16 patients had ascending aortic aneurysms with medial degeneration, 10 had acute aortic dissection, 9 had aneurysms due to chronic dissection. Control ascending aorta was obtained from organ donors and heart transplant recipients ( n = 10). Patients with Marfan syndrome were excluded from this study. CTGF mRNA expression within aortic wall was semiquantitatively determined by real-time RT-PCR using GAPDH as the internal standard. Results. There was a significant increase in CTGF mRNA in degenerative aneurysms compared to control tissue ( P = 0.04). Conversely, patients with acute dissection had decreased CTGF mRNA expression compared with nondissection aneurysms ( P = 0.019) and controls ( P = 0.06). The increase in CTGF expression in chronic dissections compared to acute dissections approached statistical significance ( P = 0.075). Conclusions. The altered tissue levels of CTGF in aneurysms and dissections suggest possibly different molecular pathology in these aortic disorders. Further investigation regarding the role of CTGF in thoracic aortic disease is warranted.

Connective tissue growth factor (CTGF/CCN2) in hepatic fibrosis

Connective tissue growth factor (CTGF/CCN2) is a highly profibrogenic molecule which is overexpressed in many fibrotic lesions, including those of the liver. CTGF/CCN2 is transcriptionally activated by transforming growth factor-beta (TGF-β) and appears to mediate some of the extracellular matrix (ECM)-inducing properties that have been previously attributed to TGF-β. CTGF/CCN2 and TGF-β stimulate connective tissue cell proliferation and ECM synthesis in vitro and exhibit shared fibrogenic and angiogenic properties in vivo. In fibrotic liver, CTGF/CCN2 mRNA and protein are produced by fibroblasts, myofibroblasts, hepatic stellate cells (HSCs), endothelial cells, and bile duct epithelial cells. CTGF/CCN2 is also produced at high levels in hepatocytes during cytochrome P-4502E1-mediated ethanol oxidation. CTGF/CCN2 expression in cultured HSCs is enhanced following their activation or stimulation by TGF-β while exogenous CTGF/CCN2 is able to promote HSC adhesion, proliferation, locomotion, and collagen production. Collectively, these data suggest that during initiating or downstream fibrogenic events in the liver, production of CTGF/CCN2 is regulated primarily by TGF-β in one or more cell types and that CTGF/CCN2 plays important roles in HSC activation and progression of fibrosis. This article reviews the data that support the importance of CTGF/CCN2 in hepatic fibrosis and highlights the concept that CTGF/CCN2 may represent a new therapeutic target in this disease.