Increased Collagen Biosynthesis Research Articles

Acceleration in healing of infected full-thickness wound with novel antibacterial γ-AlOOH-based nanocomposites.

This study was conducted to synthesize γ-AlOOH (bohemite)-based nanocomposites (NCs) of Au/γ-AlOOH-NC and its functionalized derivative using chitosan (Au/γ-AlOOH/Ctn-NC) and with the help of one-step Mentha piperita. The physicochemical characteristics of the NCs were investigated. In addition, biomedical properties, such as antibacterial activity under in vitro and in vivo conditions, and cell viability were assessed. Wound healing activity on infected wounds and histological parameters were assessed. The gene expressions of TNF-α, Capase 3, Bcl-2, Cyclin-D1 and FGF-2 were investigated. The TEM and FESEM images showed the sheet-like structure for bohemite in Au/γ-AlOOH-NC with Au nanoparticles in a range of 14-15nm. The elemental analysis revealed the presence of carbon, oxygen, aluminum, and Au elements in the as-synthesized Au/γ-AlOOH. The results for toxicity showed that the produced nanocomposites did not show any cytotoxicity. Biomedical studies confirmed that Au/γ-AlOOH-NC and Au/γ-AlOOH/Ctn-NC have anti-bacterial properties and could expedite the wound healing process in infected wounds by an increase in collagen biosynthesis. The administration of ointment containing Au/γ-AlOOH-NC and Au/γ-AlOOH/Ctn-NC decreased the expressions of TNF-α, and increased the expressions of Capase 3, Bcl-2, Cyclin-D1 and FGF-2. The novelty of this study was that bohemite and Au nanoparticles can be used as a dressing to accelerate the wound healing process. In green synthesis of Au/γ-AlOOH-NC, phytochemical compounds of the plant extract are appropriate reagents for stabilization and the production of Au/γ-AlOOH-NC. Therefore, the new bohemite-based NCs can be considered as candidate for treatment of infected wounds after future clinical studies.

Asiaticoside polymeric nanoparticles for effective diabetic wound healing through increased collagen biosynthesis: In-vitro and in-vivo evaluation

Asiaticoside (AST) is a naturally available phytoconstituent that enables effective wound healing mainly by promoting collagen biosynthesis. However, the physicochemical nature of AST such as high molecular weight (959.12 g/mol), poor water solubility and poor permeability limits its therapeutic effects. This study aims to develop Asiaticoside polymeric nanoparticles (AST PNP) embedded in a gelatin based biodegradable hydrogel (15 % w/v) for application in the wound cavity to enable sustained release of AST and enhance its therapeutic effects. The AST PNP were fabricated in the desired size range (168.4 nm; PDI (0.09)) and the morphology, rate of fluid uptake, rate of water loss, and water vapor transmission rate of AST PNP incorporated hydrogel were determined. AST PNP gel showed porous structural morphology and possessed ideal characteristics as a graft for wound healing. The drug release kinetics and cellular uptake of AST PNP were investigated wherein, AST PNP demonstrated sustained release profile upto 24 h in comparison to free AST (complete release within 6 h) and exhibited an enhanced intra-cellular uptake in fibroblasts within 3 h compared to the free drug. In-vitrocell culture studies also demonstrated significant proliferation and migration of fibroblasts in the presence of AST PNP. Additionally, AST PNP gel upon application to the wounds of diabetic rats depicted improved wound healing efficacy in terms of improved collagen biosynthesis, upregulated COL-1 protein level (∼1.85 fold vs free AST), and enhanced expression of α-SMA compared to control groups. Altogether, formulation of AST as polymeric nanoparticles in a gel based carrier offered significant improvement in the therapeutic properties of AST for the management of diabetic wounds.

Platelet-rich plasma counteracts interleukin-1 induced inhibition of collagen biosynthesis through recovery of impaired β1-integrin signaling and prolidase activity in human skin fibroblasts.

Although inflammation is the first step in wound healing, it contributes to down-regulation of collagen biosynthesis delaying the process of tissue regeneration. The study was conducted to evaluate the effects of platelet-rich plasma (PRP) on interleukin-1β (IL-1β) – dependent inhibition of collagen synthesis, prolidase activity, and β1-integrin signaling in cultured human skin fibroblasts. PRP was obtain using the SmartPReP®2 Autologous Platelet Concentrate+ System. Collagen biosynthesis and prolidase activity were measured in confluent human skin fibroblast cultures with IL-1β, PRP, hyaluronic acid (HA), and mixtures of IL-1β with PRP or HA. Immunofluorescence bioimaging analysis was employed to evaluate expression of β1 integrin receptor, cyclooxygenase-2 (COX-2) and nuclear factor-κB (NF-κB) protein. Incubation of fibroblasts with 2% PRP for 24 h contributed to about 500% increase in collagen biosynthesis and a significant increase in the expression of β1-integrin receptor and prolidase activity, compared to the control cells. In the cells treated with IL-1β, collagen biosynthesis, β1-integrin receptor expression, and prolidase activity were decreased while COX-2 and NF-κB expressions were significantly increased. All these processes were recovered to control values by PRP or HA; however, PRP was found to act more effectively than HA. It was found that PRP counteracted IL-1β -dependent inhibition of collagen synthesis through recovery of β1-integrin receptor expression and prolidase activity and down-regulation of COX-2 and NF-κB expressions in cultured fibroblasts. The data suggest that PRP evoke anti-inflammatory activity that is desirable in tissue regeneration.

Topical Administration of an Ointment Prepared From Satureja sahendica Essential Oil Accelerated Infected Full-Thickness Wound Healing by Modulating Inflammatory Response in a Mouse Model

Satureja sahendica has antibacterial and anti-inflammatory properties that can have beneficial effects for decreasing inflammation in infected wounds. This study was conducted to evaluate the effects of an ointment prepared from S sahendica essential oil (SSO) on an infected wound model in BALB/c mice. One full-thickness excisional skin wound was surgically created per animal and inoculated with 5 × 107 colony-forming units of Pseudomonas aeruginosa and Staphylococcus aureus. Following induction of the wound, the mice (N = 90) were treated with soft yellow paraffin (negative control, n = 18), mupirocin (positive control, n = 18) and 1%, 2%, and 4% SSO (n = 18 in each of the 3 groups). To determine the effect of the treatments on healing of an infected wound, the following factors were assessed: rate of the wound area, tissue bacterial count, histopathology, collagen biosynthesis, immunohistochemistry, and the expressions of insulin-like growth factor (IGF)-1, fibroblast growth factor (FGF)-2, vascular endothelial growth factor (VEGF), interleukin (IL)-1ß, IL-4, transforming growth factor beta (TGF-ß), and chemokine (CXC motif) ligand 1 (CXCL-1) on days 3, 7, and 14 after induction of the wound. Topical administration of SSO shortened the inflammatory phase, accelerated cellular proliferation, and increased fibroblast distribution per 1 mm2, collagen deposition, and rapid reepithelialization in comparison with control animals (P <.05). The messenger RNA levels of IGF-1, IL-10, FGF-2, VEGF, TGF-ß1, and CXCL-1 were remarkably increased, and IL-1ß level decreased (P <.05) in the treated animals compared with the control group (P <.05). The immunohistochemical analyses showed topical administration of SSO increased collagen biosynthesis in the treated group (P <.05). Topical administration of SSO shows evidence of accelerating wound healing by upregulating the expression of IGF-1, IL-10, FGF-2, VEGF, TGF-ß, and CXCL-1; shortening the inflammatory stage; and promoting the proliferative phase.

LEFT VENTRICULAR MASS AND URINARY METABOLOMICS IN YOUNG BLACK AND WHITE ADULTS: THE AFRICAN-PREDICT STUDY

Objective: Increased left ventricular mass is an independent predictor for cardiovascular events, and shown to be higher in black than white populations. To gain a better understanding of early factors contributing to increased left ventricular mass in young black adults, we investigated metabolomic profiles and identified metabolites associated with left ventricular mass index in healthy black and white adults aged 20–30 years. Design and method: We included normotensive black (N = 80) and white (N = 80) participants from the African-PREDICT study, with data on urinary metabolomics and echocardiography. Urinary metabolites were measured using nuclear magnetic resonance spectroscopy, liquid chromatography tandem mass spectrometry and gas chromatography time-of-flight mass spectrometry. Univariate statistical analyses, including independent t-test (adjusted for multiple comparisons), effect size (d &gt; = 0.3) and single regression analyses were used to identify metabolites. Results: When comparing the black and white groups, the black group had lower body weight (p &lt; 0.001) and protein intake (p = 0.014). Central systolic blood pressure was higher in the black group compared to the white group (p &gt; 0.005), whereas left ventricular mass index was similar between the groups (p = 0.97). Three from a total of 192 metabolites were identified to be more abundant (p &lt; 0.046) and inversely associated with left ventricular mass index in the black group only: hydroxyproline (beta = –0.24; p = 0.020), glycine (beta = –0.23; p = 0.025) and trimethylamine (beta = –0.22; p = 0.026). Conclusions: Higher urinary levels of hydroxyproline, glycine and trimethylamine were inversely associated with left ventricular mass index in the black adults only. Hydroxyproline and glycine are important in maintaining healthy collagen turnover and stability in the heart. Our results may reflect an increase in collagen biosynthesis and collagen deposition in the left ventricle due to higher central systolic blood pressure in the black population.

Left ventricular mass and urinary metabolomics in young black and white adults: The African-PREDICT study

Background and aimsIncreased left ventricular mass is an independent predictor for cardiovascular events, and shown to be higher in black than white populations. To gain a better understanding of early factors contributing to increased left ventricular mass in young black adults, we investigated metabolomic profiles, identified and compared metabolites that associated with left ventricular mass index in healthy black and white adults. Methods and resultsWe included normotensive black and white participants from the African-PREDICT study, with data on urinary metabolomics and echocardiography. Urinary metabolites were measured using three different analytical platforms. Univariate statistical analyses, including independent t-test (adjusted for multiple comparisons), effect size (d ≥ 0.3) and single regression analyses were used to identify metabolites. When comparing the black and white groups, the black group had higher central systolic blood pressure (p > 0.005), whereas left ventricular mass index was similar between the groups (p = 0.97). Three from a total of 192 metabolites were identified to be more abundant (p < 0.046) and inversely associated with left ventricular mass index in the black group only: hydroxyproline (β = −0.22; p = 0.045), glycine (β = −0.20; p = 0.049) and trimethylamine (β = −0.21; p = 0.037). ConclusionHigher urinary levels of hydroxyproline, glycine and trimethylamine were inversely associated with left ventricular mass index in the black adults only. Hydroxyproline and glycine are important in maintaining healthy collagen turnover and stability in the heart. Our results may reflect an increase in collagen biosynthesis and collagen deposition in the left ventricle due to higher central systolic blood pressure in the black population.

Molecular modeling investigation of the potential mechanism for phytochemical-induced skin collagen biosynthesis by inhibition of the protein phosphatase 1 holoenzyme.

The most prominent feature of UV-induced photoaged skin is decreased type 1 procollagen. Increase of the TGF-β/Smad signaling through inhibition of the TβRI dephosphorylation by the GADD34-PP1c phosphatase complex represents a promising strategy for the increase in type 1 collagen production and prevention of UV-induced skin photoaging. In this study, the molecular docking and dynamics simulations, and pharmacophore modeling method were run to investigate a possible binding site as well as binding modes between apigenin, daidzein, asiaticoside, obovatol, and astragaloside IV and PP1c. Through docking study, the possible binding site for these phytochemicals was predicted as the hydrophobic (PP1-substrate binding) groove. The result indicates that PP1 is the significant target of these compounds. Moreover, the 20,000-ps MD simulations present that the binding locations and modes predicted by the docking have been slightly changed considering that the MD simulations proffer more reliable details upon the protein-ligand recognition. The MM-GBSA binding free energy calculations and pharmacophore modeling rationally identify that the highly hydrophobic surfaces/pockets at close proximity of the catalytic core are the most favorable binding locations of the herbal compounds, and that some experimental facts upon a possible mechanism of increase in collagen biosynthesis can be explained. The present study theoretically offers the reliable binding target of the herbal compounds, and therefore helps to understanding the action mechanism for natural small molecules that enhance collagen production.

Proline oxidase silencing induces proline-dependent pro-survival pathways in MCF-7 cells.

Proline degradation by proline dehydrogenase/proline oxidase (PRODH/POX) contributes to apoptosis or autophagy. The identification of specific pathway of apoptosis/survival regulation is the aim of this study. We generated knocked-down PRODH/POX MCF-7 breast cancer cells (MCF-7shPRODH/POX). PRODH/POX silencing did not affect cell viability. However, it contributed to decrease in DNA and collagen biosynthesis, increase in prolidase activity and intracellular proline concentration as well as increase in the expression of iNOS, NF-κB, mTOR, HIF-1α, COX-2, AMPK, Atg7 and Beclin-1 in MCF-7shPRODH/POX cells. In these cells, glycyl-proline (GlyPro, substrate for prolidase) further inhibited DNA and collagen biosynthesis, maintained high prolidase activity, intracellular concentration of proline and up-regulated HIF-1α, AMPK, Atg7 and Beclin-1, compared to GlyPro-treated MCF-7 cells. In MCF-7 cells, GlyPro increased collagen biosynthesis, concentration of proline and expression of caspase-3, cleaved caspases -3 and -9, iNOS, NF-κB, COX-2 and AMPKβ. PRODH/POX knock-down contributed to pro-survival autophagy pathways in MCF-7 cells and GlyPro-derived proline augmented this process. However, GlyPro induced apoptosis in PRODH/POX-expressing MCF-7 cells as detected by up-regulation of active caspases -3 and -9. The data suggest that PRODH/POX silencing induces autophagy in MCF-7 cells and GlyPro-derived proline supports this process.

GYY4137, a Hydrogen Sulfide Donor Modulates miR194-Dependent Collagen Realignment in Diabetic Kidney

The relationship between hydrogen sulfide (H2S), microRNAs (miRs), matrix metalloproteinases (MMPs) and poly-ADP-ribose-polymerase-1 (PARP-1) in diabetic kidney remodeling remains mostly obscured. We aimed at investigating whether alteration of miR-194-dependent MMPs and PARP-1 causes renal fibrosis in diabetes kidney, and whether H2S ameliorates fibrosis. Wild type, diabetic Akita mice as well as mouse glomerular endothelial cells (MGECs) were used as experimental models, and GYY4137 as H2S donor. In diabetic mice, plasma H2S levels were decreased while ROS and expression of its modulator (ROMO1) were increased. In addition, alteration of MMPs-9, −13 and −14 expression, PARP-1, HIF1α, and increased collagen biosynthesis as well as collagen cross-linking protein, P4HA1 and PLOD2 were observed along with diminished vascular density in diabetic kidney. These changes were ameliorated by GYY4137. Further, downregulated miRNA-194 was normalized by GYY4137 in diabetic kidney. Similar results were obtained in in vitro condition. Interestingly, miR-194 mimic also diminished ROS production, and normalized ROMO1, MMPs-9, −13 and −14, and PARP-1 along with collagen biosynthesis and cross-linking protein in HG condition. We conclude that decrease H2S diminishes miR-194, induces collagen deposition and realignment leading to fibrosis and renovascular constriction in diabetes. GYY4137 mitigates renal fibrosis in diabetes through miR-194-dependent pathway.

Differential effect of platelet-rich plasma fractions on β1-integrin signaling, collagen biosynthesis, and prolidase activity in human skin fibroblasts.

The study was conducted to evaluate the effects of platelet-rich plasma (PRP), supernatant of PRP (SPRP) obtained by centrifugation, and supernatant of activated PRP (SActi-PRP) obtained by Ca2+ solution-treated PRP on collagen biosynthesis, prolidase activity, and β1-integrin signaling in cultured human skin fibroblasts. Incubation of fibroblasts with 5% PRP for 24 h contributed to ~5-fold increase in collagen biosynthesis compared to the control. In the cells treated with 5% of SPRP or SActi-PRP, collagen biosynthesis showed a 3-fold increase of the control. PRP, SPRP, and SActi-PRP stimulated prolidase activity similar to collagen biosynthesis. Collagen biosynthesis and prolidase activity are regulated by β1-integrin receptor signaling. Incubation of fibroblasts with PRP for 24 h contributed to a dose-dependent increase in the expression of β1-integrin receptor, while SActi-PRP increased the process to a much lower extent. SPRP had no effect on the β1-integrin receptor expression. All the studied fractions of blood increased the expression of FAK as well as the expression of phosphorylated MAP-kinases. However, PRP was found to be the most effective stimulator of expression of these particular kinases. These studies suggest that a complex of factors, including growth factors, adhesion molecules, and prolidase contained in PRP, all evoke growth and collagen-promoting activities in human dermal fibroblasts.

P0938 : Olive oil comsumption ameliorates non-alcoholic steatohepatitis induced by hypercaloric and hyperlipidic western diets

Background and Aims: Activation of hepatic stellate cells (HSC) and dysregulation of several mediators such as matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) play a determinant role in the fibrogenesis during the progression of NAFLD to NASH. This study was aimed to establish the interplay between hepatocytes and HSC in an in vitro cell model of NASH. Methods: The effect of free fatty acids (FFA) (Oleic:Palmitic, 2:1) was analyzed at short (24h) and long (96h) exposure times in different experimental set-ups: (1) Monoculture of each cell type; (2) Transwell system (soluble mediators effects) and (3) simultaneous co-culture (SCC) by seeding both cell types together (cell-to-cell interaction). In each system was assessed the amount of steatosis; expression of HSC activation marker (a-SMA), ECM turnover regulators (MMP-2 and TIMP-2) as well as collagen biosynthesis in comparison to untreated cells (ctrl). Results: The amount of steatosis was comparable among all the experimental set-ups. However, HSC activation in terms of a-SMA gene (2.20±0.25-folds; p < 0.01) and protein (1.70±0.20folds; p < 0.01) expression was only increased in the SCC and was maximal after 24h of FFA exposure. Similarly, the close contact of the two cell types induced an up-regulation of TIMP2 protein (1.42±0.27-folds; p < 0.05) which was inversely correlated both with MMP-2 protein (0.58±0.10-folds; p < 0.01) and activity (0.70±0.13folds; p < 0.05). This dysregulation was accompanied by an increase of collagen biosynthesis at longer FFA exposure times (1.5±0.10folds, p < 0.01). Any of these effects was directly induced by FFA (monoculture) nor by the soluble mediators (transwell). Conclusions: Our data suggest that hepatocytes-to-HSC proximity/interaction is essential for fibrosis initiation in NASH.

Enalapril stimulates collagen biosynthesis through prolidase-dependent mechanism in cultured fibroblasts

The mechanism of a lower incidence of dermatological manifestations in patients treated with enalapril compared to patients treated with other ACE-inhibitors, e.g., captopril, is not known. The finding that prolidase plays an important role in collagen biosynthesis and that some angiotensin-converting enzyme inhibitors affect prolidase activity led us to evaluate its effect on collagen biosynthesis in cultured human skin fibroblasts. Since insulin-like growth factor (IGF-I) and transforming growth factor beta 1 (TGF-β1) are the most potent stimulators of both collagen biosynthesis and prolidase activity, and prolidase is regulated by β1 integrin signaling, the effect of enalapril and enalaprilat on IGF-IR, TGF-β1, and β1 integrin receptor expressions was evaluated. Cells were treated with milimolar concentrations (0.3 and 0.5 mM) of enalapril and enalaprilat for 24 h. The activity of prolidase was determined by colorimetic assay. Collagen biosynthesis was evaluated by radiometric assay. Expression of signaling proteins was evaluated using Western blot. It was found that enalapril- and enalaprilat-dependent increase in prolidase activity and expression was accompanied by parallel increase in collagen biosynthesis. The exposure of the cells to 0.5 mM enalapril and enalaprilat contributed to increase in IGF-IR and α2β1 integrin receptor as well as TGF-β1 and NF-κB p65 expressions. Enalapril- and enalaprilat-dependent increase of collagen biosynthesis in fibroblasts results from increase of prolidase activity and expression, which may undergo through activation of α2β1 integrin and IGF-IR signaling as well as upregulation of TGF-β1 and NF-κB p65, the inhibitor of collagen gene expression.

The mechanism of oxythiamine-induced collagen biosynthesis in cultured fibroblasts.

The oxythiamine (OXY) is antivitamin of thiamine. The finding that OXY increases the cytoplasmic concentration of pyruvate, known to enhance collagen biosynthesis, led us to investigate the mechanism of this antivitamin action on collagen biosynthesis in cultured human skin fibroblasts. Confluent fibroblasts were treated with micromolar concentrations (30–1,000 µM) of OXY for 24 and 48 h. It was found that OXY-dependent increase in collagen biosynthesis was accompanied by parallel increase in prolidase activity and level, compared to untreated cells. Since phosphoenolpyruvate (PEP) is known as an inhibitor of prolidase—the enzyme that plays important role in collagen biosynthesis, the mechanism of pyruvate interconversion was considered as a regulatory switch in collagen biosynthesis. In fact, 3-MPA, specific inhibitor of phosphoenolpyruvate carboxykinase (PEPCK), contributed to up-regulation of prolidase activity, suggesting that down-regulation of PEP formation is an underlying mechanism. Since collagen biosynthesis and prolidase activity are regulated by signal induced by activated α2β1 integrin receptor as well as insulin-like growth factor-I receptor (IGF-IR), the expression of these receptors was measured by Western immunoblot analysis. The exposure of the cells to OXY contributed to decrease in IGF-IR, α2β1 integrin receptor, pERK1/2, and NF-κB p65 expressions. It was accompanied by increase in total ERK1/2 expression and induction of phosphorylation of Akt protein. The data suggest that OXY-dependent increase of collagen biosynthesis in cultured human skin fibroblasts results from activation of prolidase activity and level, induction in pAkt expression and down-regulation of pERK1/2 and NF-κB p65, the known inhibitor of collagen gene expression.

콜라겐 합성과 MMP-1 발현에 대한 생물전환 지실 추출물의 효과

Ponciri fructus, the unripe fruits of Poncirus trifoliata, are widely used in oriental traditional medicine as a remedy for inflammation, gastritis, emesis, digestive ulcers, allergy, and dysentery. To study the anti-wrinkle effects of Ponciri fructus extract (PFE) containing flavanone glycosides, PFE was fermented with Ganoderma lucidum mycelia and its biological activities were investigated. In Ponciri fructus extracts fermented with G. lucidum (G-PFE), polyphenol content was <TEX>$1,021.00{\pm}0.50{\mu}g/mL$</TEX> and flavonoid content was <TEX>$589.41{\pm}0.21{\mu}g/mL$</TEX>. G-PFE was found to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and superoxide anion radical by a dose dependent manner, respectively. G-PFE showed higher antioxidant activity than that of PFE. In addition, the photoprotective properties of G-PFE was tested in human dermal fibroblasts (HDF) exposed to UVA radiation. G-PFE inhibited the activity of matrix metalloproteinase-1 (MMP-1) and showed a dose dependent decrease in the expression level of MMP-1. G-PFE also increased collagen biosynthesis in HDF. These results demonstrate that G-PFE could be useful as a potential cosmetic ingredient for anti-wrinkle.

The mechanism of hydralazine-induced collagen biosynthesis in cultured fibroblasts

The finding that hydralazine (HYD) affects collagen metabolism led us to investigate the mechanism of its action on collagen biosynthesis, prolidase expression and activity, expression of α2β1 integrin, insulin-like growth factor-I receptor (IGF-IR), focal adhesion kinase (FAK), mitogen-activated protein (MAP) kinases (ERK1, ERK2), and transcription factors hypoxia-inducible factor-1α (HIF-1α) and nuclear factor-κB p65 (NF-κB p65) in human dermal fibroblasts. Confluent fibroblasts were treated with micromolar concentrations (50–500 μM) of HYD for 24 h. HYD had no influence on cell viability. It was found that HYD-dependent increase in collagen biosynthesis was accompanied by a parallel increase in prolidase activity and expression, HIF-1α expression, and decrease in DNA biosynthesis, compared to untreated cells. Since collagen biosynthesis and prolidase activity are regulated by a signal induced by activated α2β1 integrin receptor as well as IGF-IR, the expression of these receptors was measured by Western immunoblot analysis. The exposure of the cells to HYD contributed to the increase in IGF-IR expression without any effect on α2β1 integrin receptor and FAK expressions. It was accompanied by a decrease in expression of MAP kinases and NF-κB p65, the known inhibitor of collagen gene expression. The data suggest that the HYD-dependent increase of collagen biosynthesis in cultured human skin fibroblasts results from activation of IGF-IR expression and prolidase activity and downregulation of NF-κB p65.

Heparan sulfate glycosaminoglycan mimetic improves pressure ulcer healing in a rat model of cutaneous ischemia‐reperfusion injury

Pressure ulcers are a major clinical problem, with a large burden on healthcare resources. This study evaluated the effects of the heparan sulfate glycosaminoglycan mimetic, OTR4120, on pressure ulceration and healing. Ischemia-reperfusion (I-R) was evoked to induce pressure ulcers by external clamping and then removal of a pair of magnet disks on rat dorsal skin for a single ischemic period of 16 hours. Immediately after magnet removal, rats received an intramuscular injection of OTR4120 weekly for up to 1 month. During the ischemic period, normal skin perfusion was reduced by at least 60% and at least 20-45% reperfused into the ischemic region after compression release. This model caused sustained skin incomplete necrosis for up to 14 days and led to grade 2-3 ulcers. OTR4120 treatment decreased the area of skin incomplete necrosis and degree of ulceration. OTR4120 treatment also reduced inflammation and increased angiogenesis. In OTR4120-treated ulcers, the contents of vascular endothelial growth factor, platelet-derived growth factor, and transforming growth factor beta-1 were increased. Moreover, OTR4120 treatment promoted early expression of alpha-smooth muscle actin and increased collagen biosynthesis. Long-term restoration of wounded tissue biomechanical strength was significantly enhanced after OTR4120 treatment. Taken together, we conclude that OTR4120 treatment reduces pressure ulcer formation and potentiates the internal healing bioavailability.

Arginase isoenzymes in human cirrhotic liver.

Cirrhosis leads to an inability of the liver to perform its biochemical functions. It can also lead to hepatocellular carcinoma in which, as we showed lately, arginase isoenzyme pattern changes. The present work presents our results on arginase isoenzymes and their possible role in liver cirrhosis. The study was performed on tissues obtained during liver transplantation from 60 patients with liver cirrhosis, and on samples of histologically normal liver (control) from 40 patients with benign or colorectal cancer liver metastases removed during surgery, 6-7 cm from the tumor border. Arginase isoenzymes AI (so-called liver-type arginase) and AII (called extrahepatic arginase) were identified by Western blotting and isolated by ion-exchange chromatography. Their expression on mRNA level was studied by RT-PCR. A significant decrease in arginase activity, dependent of the liver clinical stage, was observed in cirrhotic tissue. Arginase AI activity and its mRNA level were significantly decreased in cirrhotic liver, whereas the activity and expression of arginase AII were concurrently raised, as compared to normal liver. Since arginase AI is a key enzyme of the urea cycle, whereas arginase AII most probably takes part in the biosynthesis of ornithine and polyamines, the defective ammonia inactivation and increased collagen biosynthesis observed in cirrhotic liver may be related to the changes in arginase AI and AII levels, respectively.

A Complete Expression Profile of Matrix-Degrading Metalloproteinases in Dupuytren’s Disease

Dupuytren's disease (DD) is a common fibrotic condition of the palmar fascia, leading to deposition of collagen-rich cords and finger contractions. The metzincin superfamily contains key enzymes in the turnover of collagen and other extracellular matrix macromolecules. A number of broad-spectrum matrix metalloproteinase inhibitors, used in cancer clinical trials, caused side effects of DD-like contractures. We tested the hypothesis that changes in the expression of specific metalloproteinases underlie or contribute to the fibrosis and contracture seen in DD. We collected tissue from patients with DD and used normal palmar fascia as a control. We profiled the expression of the entire matrix metalloproteinase (MMP), tissue inhibitor of metalloproteinases (TIMP), and a disintegrin and metalloproteinase domain with thrombospondin motif (ADAMTS) gene families in these tissues using real-time reverse-transcription polymerase chain reaction. A number of metalloproteinases and inhibitors are regulated in DD. The expression of 3 key collagenases, MMP1, MMP13, and MMP14 is increased significantly in the DD nodule, as is the expression of the collagen biosynthetic enzyme ADAMTS14. The expression of MMP7, an enzyme with broad substrate specificity, is increased in the DD nodule and remains equally expressed in the DD cord. TIMP1 expression is increased significantly in DD nodule compared with normal palmar fascia. This study measured the expression of all MMP, ADAMTS, and TIMP genes in DD. Contraction and fibrosis may result from: (1) increased collagen biosynthesis mediated by increased ADAMTS-14; (2) an increased level of TIMP-1 blocking MMP-1- and MMP-13-mediated collagenolysis; and (3) contraction enabled by MMP-14-mediated pericellular collagenolysis (and potentially MMP-7), which may escape inhibition by TIMP-1. The complete expression profile will provide a knowledge-based approach to novel therapeutics targeting these genes.

IL-6 Signaling Pathway in Keloids: A Target for Pharmacologic Intervention?

Keloids are cosmetically devastating lesions with considerable morbidity. Ghazizadeh et al. document enhanced expression of IL-6 and its receptors in keloid fibroblasts, with a concomitant increase in collagen biosynthesis. Anti-IL-6 antibodies or blocking the IL-6 receptors elicits reduced collagen synthesis, suggesting a role for IL-6 in the regulation of collagen gene expression. These observations imply the feasibility of a pharmacologic platform, based on the targeting of the IL-6 signaling pathway, in keloids.

Acetylsalicylic acid prevents nickel-induced collagen biosynthesis in human fibroblasts

Exposure to nickel compounds that occurs mainly via inhalation can have adverse effects on human health. One of them is pulmonary fibrosis that results from accumulation of collagen in lung tissues. The mechanism of this process as well as effective treatment of the disease is not known. To evaluate the effect of nickel on collagen biosynthesis human dermal fibroblasts were treated with various concentrations of nickel chloride(II) for 72 h. The compound was found to stimulate collagen biosynthesis in dose-dependent manner. We considered prolidase as a potential target for nickel-dependent collagen biosynthesis regulation. Prolidase [E.C.3.4.13.9] is a cytosolic metalloproteinase, which specifically splits imidodipeptides with C-terminal proline that is recycled for collagen biosynthesis. However, it was found that 72 h treatment of confluent cells with Ni(II) did not affect significantly prolidase activity. An addition of acetylsalicylic acid, known, non-specific inhibitor of prolidase to the cells treated with 100 μM NiCl(II), significantly reduced both collagen biosynthesis and prolidase activity. It suggests that acetylsalicylic acid prevents nickel-induced increase in collagen biosynthesis through inhibition of prolidase activity in human fibroblasts. The results indicate that tissue fibrosis may be considered as a possible target for prolidase inhibitory therapy and acetylsalicylic acid may represent such an agent for potential application in tissue fibrosis prevention or early stages of tissue fibrosis.