Decreased Collagen Production Research Articles

Signal transduction of platelet-induced liver regeneration and decrease of liver fibrosis.

Platelets contain three types of granules: alpha granules, dense granules, and lysosomal granules. Each granule contains various growth factors, cytokines, and other physiological substances. Platelets trigger many kinds of biological responses, such as hemostasis, wound healing, and tissue regeneration. This review presents experimental evidence of platelets in accelerating liver regeneration and improving liver fibrosis. The regenerative effect of liver by platelets consists of three mechanisms; i.e., the direct effect on hepatocytes, the cooperative effect with liver sinusoidal endothelial cells, and the collaborative effect with Kupffer cells. Many signal transduction pathways are involved in hepatocyte proliferation. One is activation of Akt and extracellular signal-regulated kinase (ERK)1/2, which are derived from direct stimulation from growth factors in platelets. The other is signal transducer and activator of transcription-3 (STAT3) activation by interleukin (IL)-6 derived from liver sinusoidal endothelial cells and Kupffer cells, which are stimulated by contact with platelets during liver regeneration. Platelets also improve liver fibrosis in rodent models by inactivating hepatic stellate cells to decrease collagen production. The level of intracellular cyclic adenosine monophosphate (cyclic AMP) is increased by adenosine through its receptors on hepatic stellate cells, resulting in inactivation of these cells. Adenosine is produced by the degradation of adenine nucleotides such as adenosine diphosphate (ADP) and adenosine tri-phosphate (ATP), which are stored in abundance within the dense granules of platelets.

Screening and isolation for anti-hepatofibrotic components from medicinal mushrooms using TGF-(β1-induced live fibrosis in hepatic stellate cells.

Liver fibrosis is a wound-healing response to chronic liver injury that could lead to liver failure, but treatment remains ineffective. In this study, we investigated anti-hepatic fibrosis activity of n-hexane, chloroform, ethyl acetate, and methanol extracts of mycelia from six commercially available medicinal mushrooms in submerged culture, namely Antrodia camphorata, Cephalosporium sinensis, Cordyceps mortierella, Hericium erinaceus, Ganoderma lucidum, and Armillaria mellea. Their anti-fibrotic activities were evaluated via inhibition against accumulation of TGF-β1-induced collagen deposition in CFSC-8B cells. Hex, Chl, and MeOH extracts of A. camphorata and Hex extract of A. mellea significantly decreased collagen production. Bioactivity-guided fractionation led to the identification of seven compounds using UPLC-Q-TOF-MS from the Hex Fr.2 of A. camphorata. At the molecular level, Hex Fr.2 of A. camphorata suppressed α-SMA, Collagen I, Collagen III, and Fibronectin expression induced by TGF-β1 in CFSC-8B cells as indicated by qRT-PCR analysis. They also inhibited α-SMA and Collagen I protein expression according to western blot analyses. Mechanistically, Hex Fr.2 of A. camphorata negatively regulates TGF-β1/Smad2/3 signaling. Our studies demonstrate that A. camphorata has in vitro anti-hepatofibrotic activity and that there is great potential for the discovery of new drugs for the treatment of liver fibrosis by screening more medicinal mushrooms.

The cytotoxic effects of three different bisphosphonates in-vitro on human gingival fibroblasts, osteoblasts and osteogenic sarcoma cells

IntroductionOsteonecrosis of the jaw (ONJ) is an emerging condition in patients undergoing long-term administration of bisphosphonates (BP) for the treatment of osteoporosis and hypercalcaemia associated with malignancy, multiple myeloma, and metastatic breast and prostate cancers. This is a follow-up study, its purpose was to examine the effects in-vitro of intravenous zoledronic acid (ZOL) and pamidronate (PAM) and oral alendronate (FOS) on the human oral cavity using gingival fibroblasts and osteoblasts cells and, in addition, osteogenic sarcoma cells (SaOS-2-cells). Materials and methodsHuman gingival fibroblasts, osteoblasts and SaOS-2-cells were seeded on multiple 6-well plates at a density of 5×105cells in a 4-week cell culture. Four different concentrations (1, 5, 10, 20μM) of each BP (ZOL, PAM, FOS) and pyrophosphate were used in this study. ResultsAll BP decreased collagen production and lowered cell proliferation in-vitro. ZOL was the component with most inhibitory effect. ConclusionThe findings in this study suggest that ZOL, PAM and FOS generally diminish cell proliferation and collagen production of human gingival fibroblasts, osteoblasts and SaOS-2-cells. The present follow-up study shows that not only ZOL and PAM but also FOS have a strong inhibitory effect on collagen production and cell survival in-vitro.

Early growth response-2 expression in uterine leiomyoma cells: regulation and function

To investigate the regulation of early growth response-2 (Egr-2) by transforming growth factor β3 (TGF-β3) and its functions in cultured human uterine leiomyoma smooth muscle cells. Laboratory research. Academic medical center. Primary leiomyoma cells from patients with symptomatic leiomyomata. Tissue culture followed by RNA and protein analysis. Cell proliferation, alteration in extracellular matrix component expression. In vivo mRNA levels of Egr-2 were statistically significantly higher in leiomyoma tissues compared with matched myometrial tissues, and showed a statistically significant correlation with TGF-β3 messenger RNA (mRNA) levels in leiomyoma tissues. In primary leiomyoma smooth muscle cells, TGF-β3 statistically significantly induced Egr-2 gene expression in a dose-dependent and time-dependent manner. Small interfering RNA (siRNA) knockdown of Egr-2 markedly increased the level of the proliferation marker proliferating cell nuclear antigen and the expression of proto-oncogene c-myc. On the other hand, ablation of Egr-2 stimulated collagen-1A1 and collagen-3A1 transcription and inhibited dermatopontin gene expression. However, the mRNA levels of α-smooth muscle actin and fibronectin were not affected by Egr-2 knockdown. We demonstrated that TGF-β3 regulated Egr-2 gene expression and presented evidence that Egr-2 decreases collagen production and stimulates dermatopontin gene expression.

Inactivation of endothelial proprotein convertase 5/6 decreases collagen deposition in the cardiovascular system: role of fibroblast autophagy

Proprotein convertase (PC) 5/6 belongs to a family of secretory proteases involved in proprotein proteolysis. Several studies suggest a role for PC5/6 in cardiovascular disease. Because lethality at birth of mice lacking PC5/6 precluded elucidation of its function in the adult, we generated mice in which the gene of PC5/6 (pcsk5) is specifically inactivated in endothelial cells (ecKO), which are viable and do not exhibit overt abnormalities. In order to uncover the function of PC5/6 in the cardiovascular system, the effect of ecKO was studied in aging mice. In 16 to 18-month-old ecKO mice, the left ventricle (LV) mass, media cross-sectional area of aorta and coronary arteries, and media-to-lumen ratio of mesenteric arteries were decreased. The LV presented decreased diastolic function, and mesenteric arteries showed decreased stiffness. Collagen was decreased in the LV myocardial interstitium and perivascularly in coronary arteries and aorta. Cardiovascular hypotrophy likely develops with aging, since no significant changes were observed in 2-month-old ecKO mice. Fibroblasts, as a source of collagen in myocardium and vasculature, may play a role in the decrease in collagen deposition. Fibroblasts co-cultured with ecKO endothelial cells showed decreased collagen production, decreased insulin-like growth factor (IGF)-1/Akt/mTOR signaling, and enhanced autophagic activation. PC5/6 inactivation in endothelial cells results in cardiovascular hypotrophy associated with decreased collagen deposition, decreased LV diastolic function, and vascular stiffness, suggesting a trophic role of endothelial PC5/6 in the cardiovascular system, likely mediated by IGF-1/Akt/mTOR signaling and control of autophagy.

Ski, a modulator of wound healing and scar formation in the rat skin and rabbit ear

We recently demonstrated that Ski is a novel wound healing-related factor that promotes fibroblast proliferation and inhibits collagen secretion. Here, we show that increasing local Ski expression by gene transfer not only significantly accelerated wound healing by relieving inflammation, accelerating re-epithelialization and increasing formation of granulation tissue, but also reduced scar formation by decreasing collagen production in rat dermal wounds. Similarly, ski gene transfer accelerated wound healing, reduced the protuberant height and volume of scars and increased collagen maturity in a hypertrophic scar model in the rabbit ear. Conversely, reducing Ski expression in the wound by RNA interference resulted in significantly slower wound healing and increased scar area in rat dermal wounds. We demonstrated that these effects of Ski are associated with transforming growth factor-β-mediated signalling pathways through both Smad2/3-dependent and Smad-independent pathways. Together, our results define a dual role for Ski in promoting wound healing and alleviating scar formation, identifying a new target for therapeutic approaches to preventing scar hyperplasia and accelerating wound healing.

Fibroblast Function and Wound Breaking Strength Is Impaired by Acute Ethanol Intoxication

Alcohol intoxication occurs in nearly half of all trauma patients and increases the morbidity, mortality, and healing complications of these patients. Prior studies in our laboratory and elsewhere have demonstrated impairments in re-epithelialization, angiogenesis, and inflammation in wounds following acute ethanol exposure. Clinically, acute ethanol exposure has been shown to cause an increased breakdown of wounds. To date, the mechanisms by which acute ethanol exposure modifies wound strength have received little experimental attention. To examine how ethanol influences functions critical to the development of wound strength, the effect of ethanol exposure on fibroblast proliferation and extracellular matrix production was examined. Normal human dermal fibroblasts (NHDF) were exposed to ethanol (100 mg/dl) and then examined for proliferative capacity and mRNA production of collagen I, collagen III, and lysyl oxidase (LOX). In in vivo studies, the wound breaking strength, LOX activity, collagen, and hyaluronic acid (HA) contents of wounds of ethanol-exposed (100 mg/dl) mice were examined. At 24, 48, and 72 hours after acute ethanol exposure (8 hours duration), NHDF displayed a significant impairment in proliferative capacity (up to 50% at 24 hours p < 0.001). After ethanol exposure, NHDF produced less collagen I and LOX mRNA, but more collagen III mRNA than control fibroblasts (p < 0.05). Ethanol exposure in vivo caused a reduction in wound breaking strength of up to 40% when compared to control mice (p < 0.01). LOX activity, collagen, and HA contents in the wounds of ethanol-exposed mice were significantly reduced (p < 0.01). These studies reveal that a single exposure to ethanol prior to injury can cause a significant decrease in wound breaking strength. Our studies suggest that ethanol directly impairs fibroblast function, leading to decreased collagen production. The results provide a possible explanation for how acute ethanol exposure might increase in wound complications and wound failure.

Influence of the Use of Laser Phototherapy (λ660 or 790 nm) on the Survival of Cutaneous Flaps on Diabetic Rats

The aim of this study was to assess and compare the effects of laser phototherapy (LPT) on cutaneous flaps on diabetic rats. Diabetes mellitus is characterized by high blood glucose levels. Its main complications are delayed wound healing, an impaired blood supply, and a decrease in collagen production. Cutaneous flaps are routinely used in several surgical procedures, and most failures are related to poor blood supply. LPT has been studied using several healing models. Twelve Wistar rats were randomized into three groups: group 1 (G1; diabetic animals without treatment), group 2 (G2; diabetic animals irradiated with lambda680 nm), and group 3 (G3; diabetic animals irradiated with lambda790 nm). Diabetes was induced with streptozotocin. A 2- x 8-cm cutaneous flap was raised on the dorsum of each animal, and a plastic sheet was introduced between the flap and the bed to cause poor blood supply. Nonirradiated animals acted as controls. The dose per session was 40 J/cm(2). Laser light was applied transcutaneously and fractioned on 16 contact points at the wound margins (16 x 2.5 J/cm(2)). Animal death occurred on day 8 after surgery. Specimens were taken, processed, cut, stained with eosin (HE) and sirius red, and underwent histological analysis. It is shown that accute inflammation was mostly discrete for G3. Chronic inflammation was more evident for G2. Fibroblast number was higher for G3. Angiogenesis was more evident for G3. Necrosis was more evident for G2. Statistical analysis among all groups showed significant differences (p = 0.04) on the level of acute inflammation between G1 and G3, tissue necrosis between G1 and G2 (p = 0.03), chronic inflammation between (p = 0.04), fibroblastic proliferation between G2 and G3 (p = 0.05), and neovascularization between G2 and G3 (p = 0.04). LPT was effective in increasing angiogenesis as seen on irradiated subjects and was more pronounced when IR laser light was used.

The Effect of Epigenetic Therapy on Congenital Neurogenic Bladders—A Pilot Study

To demonstrate that human smooth muscle cells derived from neurogenic bladders produce more collagen in vitro than smooth muscle cells derived from normal bladders, and that epigenetic therapy may normalize this increased collagen production. Human smooth muscle cells from normal (n = 3) and neurogenic bladders (n = 3) were cultured in normal culture media and at different concentrations of the histone deacetylase inhibitors trichostatin A, valproic acid, and the DNA methylation inhibitor 5-azacytidine (5-aza). Collagen type I and III gene expression was measured using real-time quantitative reverse transcription-polymerase chain reaction after varying doses of drug exposure. Cell viability was measured using trypan blue. The smooth muscle cells from neurogenic bladders released significantly more collagen than the normal bladder cells (mean 4.1 vs 1.8 microg/mL in control media) when grown in normal conditions. Treatment with trichostatin A at 50 ng/mL decreased the collagen level in cells from neurogenic bladders to almost normal levels (2.1 microg/mL). In addition, valproic acid treatment decreased collagen types I and III gene expression relative to controls, with maximal effect at 300 mg/mL. These treatments had little effect on cell viability. Histone deacetylase inhibitors decreased collagen production of smooth muscle cells from neurogenic bladders in vitro. These agents may be a means of effectively preventing bladder fibrosis in patients with this condition.

Biocompatibility of polyhydroxyalkanoate as a potential material for ligament and tendon scaffold material

There is a strong need for new biodegradable materials that are suitable for scaffolds in tissue engineering of tendons and ligaments. In many cases, quick degradation rates are favorable, however, with respect to ligament and tendon replacement, slowly degrading polymers are clearly favored. Prime candidates are members of the large class of polyhydroxyalkanoates (PHAs), which are thermoplastic/elastomeric biopolyesters that are slowly degraded by surface erosion. Moreover, their physico-mechanical properties can be tailored during biosynthesis in bacteria or by chemical modifications. They may be spun into fibers, coated on surfaces or be part of composites. This study has investigated the biocompatability of seven different thermoplastic or elastomeric PHAs using L929 murine fibroblast cells. Cell viability and proliferation over 7 days was analyzed with live/dead staining and a picogreen assay. In addition, extracellular matrix production was measured with the hydroxyproline assay after 14 days. It was found that cell attachment to the PHA film ranged from 85-99% after 7 days. Three PHA films (PHBV (92/8), PHOUE-POSS and PHUE-O3) supported similar cell viability in comparison to the controls performed on tissue culture plastic (polystyrene), whereas the biomaterials (PHUA, PHUE, PHB and PHOUE) showed fewer viable cells than in controls. PHB, PHUE-O3, and PHBV with a water contact angle below 85 degrees supported a similar amount of collagen production in comparison to the tissue culture plastic controls. PHUA, PHUE, PHOUE, and PHOUE-POSS showed a decrease in collagen production in comparison to the controls after 14 days. Overall, PHB, PHBV, and PHUE-O3 demonstrated good performance with regards to potential use as a tissue-engineering scaffold.

Extracellular matrix expression of human prolapsed vaginal wall

To compare the mRNA expression of extracellular matrix (ECM) proteins in postmenopausal prolapsed versus non-prolapsed anterior vaginal wall (AVW) tissue. We hypothesized that the weakening of the tissue leading to prolapse was due to decreased collagen production from a downregulation at the transcriptional level. Following IRB approval, full thickness samples of redundant AVW were excised from consecutive age-equivalent, postmenopausal, women undergoing cystocele repair (prolapse, stage III or IV), or radical cystectomy (control, no clinical findings of prolapse). Total RNA was isolated, cDNA was synthesized, and quantitative real-time polymerase chain reaction (PCR) was conducted to assess the mRNA expression of collagens type I and III, pro-elastin, MMP3, MMP10, and MMP11. The significance of the difference of mRNA expression between prolapse and control tissues was tested using Student's t-test followed by Mann-Whitney Rank Sum Test. A 5.3-fold increase in collagen type I mRNA was found in prolapse (n = 47) over control (n = 7) tissues (P = 0.009). Type III collagen mRNA was also significantly increased to a 3.3 times higher level (P = 0.017). The ratio of type III to type I was decreased from 15.6 in controls to 9.7 in prolapse. An increasing trend in pro-elastin and MMP mRNA expression was found in prolapse, but this was not statistically significant. In this controlled study, the increase found in collagen mRNA expression disproved our hypothesis. To the contrary, this defective prolapsed tissue can signal its need for ECM replenishment. The message, however, is not being effectively translated to assist in tissue remodeling.

Avoiding dermal filler complications

Age-related volume loss; increased skin laxity, fat loss, and redistribution; and diminished support from underlying muscle and bone result in the observable and sometimes profound changes seen in the aging face. Aging also is associated with functional changes in the skin, such as dermal atrophy with diminished fibroblastic activity, decreased collagen production, and altered clastin. Dermal fillers, such as bovine, human, and purified porcine collagen; hyaluronic acids; calcium hydroxylapatite; and injectable medical devices (eg, poly-L-lactic acid), are used commonly for facial rejuvenation. Soft-tissue augmentation with fermal fillers and injectable medical devices has gained widespread acceptance as an alternative to more aggressive, invasive treatment of the aging face. Technique, knowledge, expertise with fillers, proper patient assessment, a well-formulated treatment plan with access to agents for superficial, moderate, and deep rhytides, and volume restoration provide the necessary ingredients for optimal soft-tissue augmentation while minimizing complications.

INHIBITORY EFFECT OF EMODIN ON BLEOMYCIN‐INDUCED PULMONARY FIBROSIS IN MICE

1. Currently, there is no satisfactory treatment for pulmonary fibrosis. Emodin, a component in Chinese herbs, has been shown to have an antifibrotic effect on pancreatic fibrosis and liver fibrosis. In the present study, we tested the hypothesis that emodin may attenuate the development of pulmonary fibrosis. 2. Mice were randomly divided into five groups (n = 16 in each). One group was a control group; the remaining four groups were treated with intratracheal instillation of 3 mg/kg bleomycin (BLM). The following day, emodin (5, 10 or 20 mg/kg per day, p.o.) treatment was started for three of the BLM-treated groups and was continued for 21 days. The fourth BLM-treated group (and the control group) received daily 0.5% sodium carboxymethyl cellulose (placebo) by gavage over the same period. 3. Bleomycin challenge provoked severe pulmonary fibrosis, with marked increases in fibrosis fraction, hydroxyproline content and myeloperoxidase activity in lung tissue. Emodin treatment (10 and 20 mg/kg per day, p.o.) attenuated all these biochemical indices, as well as histopathological alterations induced by BLM. Furthermore, in mice injected with BLM, elevated levels of transforming growth factor-beta1, interleukin (IL)-4 and IL-13 were found in bronchoalveolar lavage fluid. These increases were significantly inhibited by 10 and 20 mg/kg per day emodin. 4. In cell culture, exposure of cells to 6.25, 12.5, 25 or 50 micromol/L emodin for 24 h decreased fibroblast proliferation. Treatment of cells with the same concentrations of emodin for 72 h decreased collagen production by fibroblasts. In addition, emodin (6.25, 12.5, 25 or 50 micromol/L) inhibited the steady state expression of alpha1 (I) procollagen and alpha2 (I) procollagen mRNA in a dose-dependent manner. 5. The results of the present study suggest that emodin may be effective in the treatment of pulmonary fibrosis.

Efficacy of Imatinib Mesylate in the Treatment of Refractory Sclerodermatous Chronic Graft-Versus-Host Disease.

Outcomes in the treatment of sclerodermatous chronic graft-versus-host disease (cGVHD) are generally disappointing. Imatinib mesylate enables selective, dual inhibition of the transforming growth factor beta (TGFβ) and platelet-derived growth factor (PDGF) pathways. Recently, the drug's effects on fibroblasts have been reported in both in vitro and in vivo studies. Inhibiting fibroblast growth (and thus decreasing collagen production in dermal fibroblasts) is thus a logical therapeutic approach. Here, we report on our experience with 12 patients who received imatinib mesylate for refractory sclerodermatous cGVHD following allogeneic stem cell transplantation (allo-SCT). The patients' characteristics were as follows: median age, 35 years (range: 15–59); 7 male recipients, 6 female donors; 4 cases of CML, 4 MDS, 2 ALL and 2 Hodgkin's lymphoma. The patients had received either myelo-ablative conditioning with standard GVHD prophylaxis based on cyclosporine and short-course MTX (n=9) or nonmyelo-ablative conditioning with cyclosporine and MMF. Seven patients received a marrow graft and 5 received a peripheral blood graft. All displayed refractory, chronic, sclerodermatous GHVD with at least 3 lines (range 3–6) of prior immunosuppressive therapy. The modified Rodnan skin score was used to assess the extent of skin damage. Glivec was initiated at a dose of 400 mg/day between 16 and 119 months post-transplantation (median: 44). Despite an imatinib dose reduction and the administration of various symptomatic treatments, 4 patients (33%) had to discontinue their treatment soon after its initiation (range: 16–64 days) because of intolerance (especially muscle cramps) and were not evaluable in terms of the efficacy criterion. Other side effects reported were parenthesis, diarrhea and edema. In the remaining patients, the scleroderma symptoms improved within three months of treatment initiation. At the time of this report, all patients were alive and those who tolerated imatinib mesylate have experienced a complete or near-complete response (n=4) or partial response (n=4). All responders (except for one who discontinued the drug 157 days after initiation, due to cramps) were still on the treatment, after a median time period of 216 days (range: 80–2053). This retrospective report shows that when imatinib mesylate is well tolerated, it is effective in patients with refractory sclerodermatous cGVHD and is thus a promising candidate for the treatment of this complication. This study should provide useful background information for building prospective, multicenter studies.

Efficacy of imatinib mesylate in the treatment of refractory sclerodermatous chronic GVHD

Treatment of sclerodermatous chronic GVHD (cGVHD) remains disappointing. Imatinib mesylate enables selective, dual inhibition of the transforming growth factor beta (TGFbeta) and PDGF pathways. Recently, the drug's effects on fibroblasts have been reported in both in vitro and in vivo studies. The inhibition of fibroblast growth and decreased collagen production in dermal fibroblasts is thus a logical therapeutic approach. Two patients who developed refractory sclerodermatous cGVHD following allo-SCT received imatinib mesylate at the dose of 400 mg/day. In both patients, the scleroderma symptoms disappeared within 3 months of initiation of the treatment. At the time of this report, the two patients were both alive and had a very good skin response. This report shows that imatinib is effective in patients with refractory sclerodermatous cGVHD. Considering its well-documented clinical profile in other diseases, imatinib is a promising candidate for the treatment of sclerodermatous cGVHD.

Mechanisms of Arterial Remodeling in Hypertension

Diverse data collected over the past 4 decades suggest the existence of a mechanical homeostasis across multiple length and time scales in the vasculature. For example,1 stress fibers within endothelial and vascular smooth muscle cells appear to disassemble and then reassemble in a mechanically preferred manner when perturbed from a normal value of mechanical stress or strain; focal adhesions in smooth muscle cells and fibroblasts tend to increase in area in response to local increases in mechanical loading so as to maintain the stress constant at a preferred value; fibroblasts tend to increase the tractions that they exert on the extracellular matrix when external loads are decreased from a preferred value, thus suggesting an attempt to enforce a “tensional homeostasis”; vascular smooth muscle cells tend to relengthen to their normal, preferred values when an arteriole is forced into a vasoconstricted state for an extended period; and arteries tend to decrease in caliber in response to sustained decreases in flow-induced wall shear stress, to increase in thickness in response to sustained increases in pressure-induced circumferential stress, and to lengthen in response to extension-induced increases in axial stress. Although changes in the cytoskeleton and integrins occur within minutes, changes at the cell-cell and cell-matrix levels occur over hours, and those at the vessel level occur over days to weeks or months. Hence, despite marked differences in length scales (dimensions from nanometers to centimeters) and time scales (durations from minutes to months), mechanobiological control mechanisms in the vasculature tend to restore values of stress or strain toward preferred (homeostatic) values in response to diverse perturbations from normal.2–5 Biomechanics and mechanobiology thus play key roles in vascular development, tissue maintenance in maturity, normal adaptations, aging, disease progression, and responses to injury or clinical interventions. A current challenge in hypertension research is to …

Lung Function and IFN-γ Levels in the Sera of Silica-Exposed Workers

Excessive exposure to respirable particles of crystalline silica is an occupational health problem in developing countries and can cause a variety of pulmonary diseases, such as silicosis, chronic obstructive pulmonary disease (COPD), and malignancy, in susceptible hosts. In addition to the well-documented role of pulmonary macrophages, lymphocytes occasionally have been suggested to influence the pneumoconiotic process, but their potential role is not clearly understood. Interferon-gamma (IFN-gamma), a lymphocyte cytokine, is recognized as the most important cytokine in converting macrophages from a resting to an activated state. The aim of the present study was to investigate serum IFN-gamma levels and pulmonary function changes in silica-exposed workers and in silicosis. Twenty-seven silica workers (aged 35.6 +/- 8.2 years with 5.11 +/- 2.98 years exposure duration) and 18 unexposed office workers (aged 33.8 +/- 12 years) were included in the study. Mean spirometry parameters and smoking history were comparable to the values of the office workers, but COPD prevalence was higher in the silica-exposed group, and the age-adjusted ratio was more sensitive than fixed quotient criteria for airway obstruction. We found silicosis in 4 silica workers. The mean serum IFN-gamma level was increased in silica-exposed workers (10.22 +/- 22.68 pg/mL) although it was undetectable in all office workers and even in the workers with silicosis. Evaluating pulmonary function tests (PFT) using an age-adjusted quotient may prevent underestimation of airflow limitation, especially in the young population with risk factors. Although serum IFN-gamma may increase initially in response to silica, low levels of IFN-gamma in later stages may be considered a risk factor for silicosis because this cytokine downregulates the fibroblast responses to transforming growth factor-beta (TGF-beta) and decreases collagen production. Additional research to determine the exact role of this potent cytokine may offer insight into the pathogenesis of silicosis.

Matrix Proteolytic Activity During Wound Healing: Modulation by Acute Ethanol Exposure

Clinical studies demonstrate that intoxicated patients exhibit an increased incidence of wound healing complications. Previous studies in a murine excisional wound model revealed that acute ethanol exposure impairs the wound healing response, causing decreased angiogenesis and a significant reduction in wound collagen content. Using the same murine model of excisional wounding, we examined the effect of a single dose of ethanol on the overall collagen content and collagen type I and type III mRNA expression, transforming growth factor-beta (TGF-beta) production, and levels of several components of the extracellular matrix proteolytic cascade. Wounds from ethanol-treated mice exhibited a significant decrease in collagen and in the production of collagen type I mRNA compared with saline controls. Exposure to ethanol also caused significant increase in wound TGF-beta by day 2 after injury (1.69 +/- 0.29 vs 12.34 +/- 3.97 pg/microg protein, p<0.01). In addition, wounds from mice exposed to ethanol had significantly increased levels of active urokinase plasminogen activator at day 7, (205.10 +/- 48.79 vs 642.70 +/- 159.80 pg/microg protein, p<0.001). The level of matrix metalloproteinase-8, a collagen type I proteinase, was 2.2-fold higher in wounds of ethanol-treated mice compared with control at day 7 (p<0.05). These studies demonstrate that a single dose of ethanol decreases collagen production, increases the production of TGF-beta and increases levels of matrix degrading enzymes. This alteration in protease balance may partially explain the impaired wound healing that follows acute alcohol intoxication.

The comparison of IL-6, elastase and α-PI expressions in human chronic periodontitis with type 2 diabetes mellitus

Diabetes mellitus is an important risk factor of periodontal diseases. It is one of the main contributing factors for periodontal disease and also limiting factor for periodontal treatments such as implant therapy. Although diabetes itself does not cause periodontitis, periodontal disease progresses more rapidly and leads to more tooth losses in patients with poorly controlled blood glucose. Severe periodontitis has been associated with an increased risk of poor glycemic control and, in turn untreated advanced periodontal disease can deteriorate the metabolic control of diabetes. Various pathogenetic factors have been suggested to explain the increased prevalence and severity of periodontitis in diabetes.1) Reduced polymorphonuclear leukocyte(PMN) function has been found in patients with diabetes. This impairment of function was noted in assays of PMN chemotaxis, adherence and phagocytosis. Studies of PMN defects suggest that this dysfunction could lead to impaired host resistance to infection. Gingival fibroblasts from diabetic patients synthesize less collagen compared to non-diabetic subjects. In addition to decreased collagen production, crevicular fluid collagenolytic activity also was increased in diabetic patients. This increased crevicular fluid collagenase activity appears to be primarily of neutrophil origin. Non-enzymatic glycosylation process results in increased cross-linking between collagen molecules. This cross-linking of collagen significantly contributes to reduced solubility and de-

Decorin-mediated Transforming Growth Factor-β Inhibition Ameliorates Adverse Cardiac Remodeling

Implantation of a left ventricular assist device (LVAD) has been shown to induce regression of fibrosis in patients with congestive heart failure (CHF) and improve myocardial function. The mechanism of reverse remodeling after mechanical circulatory support (MCS), however, has not been fully characterized. In this study we examined the anti-fibrotic effects of decorin, an extracellular matrix (ECM) proteoglycan, on the transforming growth factor-beta (TGF-beta) pathway. Human myocardial tissue samples were obtained from patients undergoing LVAD implantation and again following subsequent transplantation after a sustained period of MCS. The specimens were examined by utilizing different molecular and histologic techniques, including human cardiac fibroblast in vitro studies. We assessed gene expression, mRNA and protein levels. We found a significant decrease in interstitial fibrosis after MCS, with a decrease in collagen mRNA transcription rates, serving as an indirect measurement of collagen synthesis. Both the mRNA and protein levels of decorin were significantly increased after a period of MCS. Decorin mRNA was up-regulated by 44% after MCS (p < 0.01), which paralleled the increase in interstitial decorin deposition (p < 0.001). In addition, p-SMAD2, a molecular marker downstream of the TGF-beta pathway, was found to be inactivated after MCS (p < 0.02). Moreover, cultured human cardiac fibroblasts exposed to TGF-beta demonstrated decreased collagen production when exogenous decorin was added (p < 0.03). The decorin molecule is potentially involved in reverse cardiac remodeling, by directly inhibiting the TGF-beta pathway and its pro-fibrotic effects on the failing human heart.