Vasoactive hormone adrenomedullin and its binding protein: anti-inflammatory effects by up-regulating peroxisome proliferator-activated receptor-gamma

Sepsis is a critical inflammatory condition from which numerous patients die due to multiple organ failure and septic shock. The vasoactive hormone adrenomedullin (AM) and its binding protein (AMBP-1) are beneficial in sepsis by abrogating the progression to irreversible shock and decreasing proinflammatory cytokine release. To investigate the anti-inflammatory mechanism, we studied to determine the effect of the AM/AMBP-1 complex on peroxisome proliferator-activated receptor-gamma (PPAR-gamma) expression and activation by using RAW264.7 cells and a rat endotoxemia model. LPS treatment significantly decreased PPAR-gamma expression in vivo and in vitro and was associated with increased TNF-alpha production. Treatment with AM/AMBP-1 for 4 h completely restored PPAR-gamma levels in both models, resulting in TNF-alpha suppression. In a knockdown model using small interfering RNA in RAW264.7 macrophages, AM/AMBP-1 failed to suppress TNF-alpha production in the absence of PPAR-gamma. LPS caused the suppression of intracellular cyclic AMP (cAMP), which was prevented by simultaneous AM/AMBP-1 treatment. Although incubation with dibutyryl cAMP significantly decreased LPS-induced TauNuF-alpha release, it did not alter PPAR-gamma expression. Through inhibition studies using genistein and PD98059 we found that the Pyk-2 tyrosine kinase-ERK1/2 pathway is in part responsible for the AM/AMBP-1-mediated induction of PPAR-gamma and the anti-inflammatory effect. We conclude that AM/AMBP-1 is protective in sepsis due to its vasoactive properties and direct anti-inflammatory effects mediated through both the cAMP-dependent pathway and Pyk-2-ERK1/2-dependent induction of PPAR-gamma.     

Fetal wound healing: a biochemical study of scarless healing

Human fetal surgery is being successfully performed today in a small number of highly selected patients for conditions that may lead to irreversible damage to the fetus and threaten the viability of the newborn. Following surgical repair, fetal wounds heal without scarring. This study was initiated to characterize fetal wounds both histologically and biochemically. Gore-Tex tubing was implanted into the subcutaneous tissue of the back of fetal, newborn, and adult New Zealand white rabbits. Light microscopic examination of healed wounds revealed no evidence of scar formation. Electron microscopy demonstrated a striated fibrillar structure suggestive of collagen within the lumen of the Gore-Tex tubing implants. Amino acid analysis (sensitivity 40 pmol) confirmed the presence of hydroxylysine and hydroxyproline within the Gore-Tex wound chambers indicating the presence of collagen in fetal wounds. The small amount of collagen precluded the typing of the collagen using cyanogen bromide peptide analysis. The absence of scarring and the small amounts of detectable collagen suggest a high degree of reorganization of the connective tissues involved in repair. The fetal wound matrix is rich in hyaluronic acid. Topical hyaluronic acid has been associated experimentally with a reduced amount of scarring in postnatal wound healing. Hyaluronic acid extracted from human skin and scar tissue is associated with collagen and other proteins. We propose that a hyaluronic acid-collagen-protein complex may play a role in fetal wound healing.     

Time course and localization of DNA synthesis during wound healing of potato tuber tissue

DNA synthesis is induced in potato tuber tissue by wounding and starts after a lag period of about 8 hr. As demonstrated by the incorporation of labeled precursors, it reaches its peak between 14 and 18 hr after cutting, and returns to the initial low level before 24 hr, the time of first cell divisions. DNA synthesis is confined to those 2 or 3 cell layers below the wound, where cell division and starch degradation are observed later. Protein synthesis and increase in respiration extend much deeper into the tissue. Both the time course of DNA synthesis and its spatial distribution show patterns different from those of other wound-induced metabolic activities. As wound healing in potato tuber tissue involves the establishment of specific patterns with respect to the time course of induced metabolic activities as well as their spatial distribution, it should be considered and studied as a developmental process. The practical advantages of the system are discussed.     

Modelling the interaction of keratinocytes and fibroblasts during normal and abnormal wound healing processes

The crosstalk between fibroblasts and keratinocytes is a vital component of the wound healing process, and involves the activity of a number of growth factors and cytokines. In this work, we develop a mathematical model of this crosstalk in order to elucidate the effects of these interactions on the regeneration of collagen in a wound that heals by second intention. We consider the role of four components that strongly affect this process: transforming growth factor-β, platelet-derived growth factor, interleukin-1 and keratinocyte growth factor. The impact of this network of interactions on the degradation of an initial fibrin clot, as well as its subsequent replacement by a matrix that is mainly composed of collagen, is described through an eight-component system of nonlinear partial differential equations. Numerical results, obtained in a two-dimensional domain, highlight key aspects of this multifarious process, such as re-epithelialization. The model is shown to reproduce many of the important features of normal wound healing. In addition, we use the model to simulate the treatment of two pathological cases: chronic hypoxia, which can lead to chronic wounds; and prolonged inflammation, which has been shown to lead to hypertrophic scarring. We find that our model predictions are qualitatively in agreement with previously reported observations and provide an alternative pathway for gaining insight into this complex biological process.     

Tissue transglutaminase in normal and abnormal wound healing: Review article

Summary. A complex series of events involving inflammation, cell migration and proliferation, ECM stabilisation and remodelling, neovascularisation and apoptosis are crucial to the tissue response to injury. Wound healing involves the dynamic interactions of multiple cells types with components of the extracellular matrix (ECM) and growth factors. Impaired wound healing as a consequence of aging, injury or disease may lead to serious disabilities and poor quality of life. Abnormal wound healing may also lead to inflammatory and fibrotic conditions (such as renal and pulmonary fibrosis). Therefore identification of the molecular events underlying wound repair is essential to develop new effective treatments in support to patients and the wound care sector.Recent advances in the understating of the physiological functions of tissue transglutaminase a multi functional protein cross-linking enzyme which stabilises tissues have demonstrated that its biological activities interrelate with wound healing phases at multiple levels. This review describes our view of the function of tissue transglutaminase in wound repair under normal and pathological situations and highlights its potential as a strategic therapeutic target in the development of new treatments to improve wound healing and prevent scarring.     

Arginase I induction by modified lipoproteins in macrophages: a peroxisome proliferator-activated receptor-gamma/delta-mediated effect that links lipid metabolism and immunity

Macrophages are phagocytic cells that play essential roles in innate immunity and lipid homeostasis. The uptake of modified lipoproteins is an important early event in the development of atherosclerosis. We analyzed the ability of modified low-density lipoprotein (LDL) (oxidized and acetylated) to alter the expression and activity of arginases (ArgI and ArgII) in macrophages. We show that ArgI expression is potently induced by both oxidized and acetylated LDL in macrophages. We further show that this effect is mediated by peroxisome proliferator-activated receptors (PPAR). ArgI expression is highly responsive to agonists for PPARgamma and PPARdelta but not PPARalpha. Moreover, the induction of ArgI by both PPAR agonists and IL-4 is blocked in macrophages from PPARgamma- and PPARdelta-deficient mice. Functionally, PPAR activity induces macrophage activation toward a more Th2 immune phenotype in a model of Leishmania major infection. We show that PPARgamma and -delta ligands promote intracellular amastigote growth in infected macrophages, and this effect is dependent on both PPAR expression and Arg activity. Collectively, our results strongly suggest that ArgI is a key marker of the alternative program triggered by PPAR in macrophages.     

In vitro anti-inflammatory and wound healing properties of Andrographis echioides and Andrographis paniculata

Andrographis echioides (L.) is an annual herbaceous plant in the family Acanthaceae. Anti-inflammatory is the property of a substance or treatment that reduces inflammation or swelling. Antioxidants are substances that can prevent or slow damage to cells caused by free radicals, unstable molecules that the body produces as a reaction to environmental and other pressures. They are sometimes called "free-radical scavengers. Therefore, it is of interest to analyse the anti-inflammatory and antioxidant properties of Andrographis echioides and Andrographis paniculata. Protease inhibitor activity was done by bovine serum albumin was added to 100µl of plant sample with increase in concentrations (100-500µg/ml). Invitro antioxidant activity was done by DPPH free radical scavenging assay. 200 µL of 0.1 mM DPPH prepared in methanol was added to 100 µL of the plant extract with increase in concentration. Based on the results from the present study, it can be concluded that A.echioides is found to be a good natural antioxidant source and A. paniculata is found to be a good anti-inflammatory source. However, both the plant A.echioides and A.paniculata have these properties. Data shows that both A.echioides and A. paniculata have potential anti-inflammatory and antioxidant activity which could be due to the presence of bioactive compounds present in the plant extracts.     

The time course and persistence of "concurrent contraction" during normal peristalsis

Whereas conventional manometry depicts peristalsis as pressure variation over time, high-resolution manometry makes it equally feasible to depict pressure variation along the lumen (spatial pressure variation plots). This study analyzed the characteristics of spatial pressure variation plots during normal peristalsis. High-resolution manometry studies of 72 normal subjects were analyzed with custom MATLAB programs. A coordinate-based strategy was used to normalize both timing of peristalsis and esophageal length. A spatial pressure variation function was devised to localize the proximal (P) and the distal troughs (D) on each subject's composite pressure topography and track the length within the P-D segment contracting concurrently in the course of peristalsis. The timing at which this function peaked was compared with that of the contractile deceleration point (CDP). The length of concurrent contraction during normal peristalsis had an average span of 9.3 cm, encompassing 61% of the distal P-D length of the esophagus. The timing of the CDP position closely matched that of maximal length within the P-D segment contracting concurrently (r = 0.90, P < 0.001). The pressure morphology of the maximal concurrent contraction was that of a smooth curve, and it was extremely rare to see multiple peaks along the vertical axis (seen in 4 of 72 subjects). Concurrent contraction involving ～60% of the P-D span occurred with normal peristalsis. The segment of concurrent contraction progressively increased as peristalsis progressed, peaked at the CDP, and then progressively decreased. How abnormalities of the extent or timing of concurrent contraction relate to clinical syndromes requires further investigation.     

Nuclear receptor peroxisome proliferator-activated receptor-gamma is activated in rat microglial cells by the anti-inflammatory drug HCT1026, a derivative of flurbiprofen

The peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is constitutively expressed in primary cultures of rat microglia, the main population of brain resident macrophages, and its ligand-dependent activation leads to the repression of several microglial functions. A few non-steroidal anti-inflammatory drugs (NSAIDs), e.g. indomethacin and ibuprofen, show PPAR-gamma agonistic properties. It has been proposed that PPAR-gamma activation contributes to the potential benefits of the long-term use of certain NSAIDs in delaying the progression of Alzheimer's disease (AD). Previous data have shown that the NSAID HCT1026 [2-fluoro-alpha-methyl(1,1'-biphenyl)4-acetic acid-4-(nitrooxy)butyl ester], a derivative of flurbiprofen which releases nitric oxide (NO), reduces the number of reactive microglial cells in a variety of models. This evidence together with the chemical analogy with ibuprofen led us to investigate whether flurbiprofen and HCT1026 interact with PPAR-gamma and interfere with microglial activation. We found that a low concentration (1 microm) of HCT1026, but not flurbiprofen, activated PPAR-gamma in primary cultures of rat microglia, with kinetics similar to those of the synthetic agonist ciglitazone. The PPAR-gamma antagonist GW9662 (2-chloro-5-nitrobenzanilide) prevented the activation of PPAR-gamma by HCT1026. Interestingly, unlike other NSAIDs that activate PPAR-gamma at concentrations higher than those required for cyclooxygenase inhibition, HCT1026 activated PPAR-gamma and inhibited prostaglandin E2 synthesis at the same low concentration (1 microm). The results suggest that HCT1026 may exert additional anti-inflammatory actions through PPAR-gamma activation, allowing a more effective control of microglial activation and brain inflammation.     

Development of an oral mucosa model to study host-microbiome interactions during wound healing

Crosstalk between the human host and its microbiota is reported to influence various diseases such as mucositis. Fundamental research in this area is however complicated by the time frame restrictions during which host-microbe interactions can be studied in vitro. The model proposed in this paper, consisting of an oral epithelium and biofilm, can be used to study microbe-host crosstalk in vitro in non-infectious conditions up to 72 h. Microbiota derived from oral swabs were cultured on an agar/mucin layer and challenged with monolayers of keratinocytes grown on plastic or collagen type I layers embedded with fibroblasts. The overall microbial biofilm composition in terms of diversity remained representative for the oral microbiome, whilst the epithelial cell morphology and viability were unaffected. Applying the model to investigate wound healing revealed a reduced healing of 30 % in the presence of microbiota, which was not caused by a reduction of the proliferation index (52.1–61.5) or a significantly increased number of apoptotic (1–1.13) or necrotic (32–30.5 %) cells. Since the model allows the separate study of the microbial and cellular exometabolome, the biofilm and epithelial characteristics after co-culturing, it is applicable for investigations within fundamental research and for the discovery and development of agents that promote wound healing.     

Failure of prostaglandins to modulate the time course of blood flow during dynamic forearm exercise in humans

Shoemaker, J. K., H. L. Naylor, Z. I. Pozeg, and R. L. Hughson. Failure of prostaglandins to modulate the time course ofblood flow during dynamic forearm exercise in humans.J. Appl. Physiol. 81(4):1516-1521, 1996.The time course and magnitude of increases inbrachial artery mean blood velocity (MBV; pulsed Doppler), diameter(D; echo Doppler), mean perfusionpressure (MPP; Finapres), shear rate ( = 8 ^· MBV/D), andforearm blood flow (FBF = MBV ^· r²)were assessed to investigate the effect that prostaglandins (PGs) haveon the hyperemic response on going from rest to rhythmic exercise inhumans. While supine, eight healthy men performed 5 min of dynamichandgrip exercise by alternately raising and lowering a 4.4-kg weight(~10% maximal voluntary contraction) with a work-to-rest cycle of1:1 (s/s). When the exercise was performed with the arm positionedbelow the heart, the rate of increase in MBV and wasfaster compared with the same exercise performed above the heart.Ibuprofen (Ibu; 1,200 mg/day, to reduce PG-induced vasodilation) andplacebo were administered orally for 2 days before two separate testingsessions in a double-blind manner. Resting heart rate was reduced inIbu (52 ± 3 beats/min) compared with placebo (57 ± 3 beats/min)(P < 0.05) without change to MPP.With placebo, D increased in both armpositions from ~4.3 mm at rest to ~4.5 mm at 5 min of exercise(P < 0.05). This response was notaltered with Ibu (P > 0.05). Ibudid not alter the time course of MBV or forearm blood flow(P > 0.05) in either arm position. The was significantly greater in Ibu vs. placebo at 30 and 40 s of above the heart exercise and for all time points after 25 sof below the heart exercise (P < 0.05). Because PG inhibition altered the time course of at the brachial artery, but not FBF, it was concludedthat PGs are not essential in regulating the blood flow responses todynamic exercise in humans.

     

Profiling of zinc-altered gene expression in human prostate normal vs. cancer cells: a time course study

We have demonstrated that zinc exposure induces apoptosis in human prostate cancer cells (PC-3) and benign hyperplasia cells (BPH), but not in normal prostate cells (HPR-1). However, the mechanisms underlying the effects of zinc on prostate cancer cell growth and zinc homeostasis remain unclear.To explore the zinc effect on gene expression profiles in normal (HPR-1) and malignant prostate cells (PC-3), we conducted a time course study of Zn treatment with microarray analysis. Microarray data were evaluated and profiled using computational approach for the primary and secondary data analyses. Final analyses were focused on the genes (1) highly sensitive to zinc; (2) associated with zinc homeostasis, i.e., metallothioneins (MTs), solute zinc carriers (ZIPs) and zinc exporters (ZnTs); (3) relevant to several oncogenic pathways. Zinc-mediated mRNA levels of MT isotypes were further validated by semi-quantitative RT-PCR.Results showed that zinc effect on genome-wide expression patterns was cell-type specific, and zinc appeared to have mainly down-regulatory effects on thousands of genes (1953 in HPR-1; 3534 in PC-3) with a threshold of ±2.5-fold, while fewer genes were up-regulated (872 in HPR-1; 571 in PC-3). The patterns of zinc effect on functional MT genes' expression provided evidence for the cell type-dependent zinc accumulation and zinc-induced apoptosis in prostate cells. In PC-3 cells, zinc significantly up-regulated the expression of MT-1 isotypes MT-1J and MT-1M, denoted previously as “nonfunctional” MT genes, and now a depictive molecular structure of MT-1J was proposed. Examination of genes involved in oncogenic pathways indicated that certain genes, e.g., Fos, Akt1, Jak3 and PI3K, were highly regulated by zinc with cell-type specificity.This work provided an extensive database on zinc-related prostate cancer research. The strategy of data analysis was devoted to finding genes highly sensitive to Zn, and the genes associated with zinc accumulation and zinc-induced apoptosis. The results indicate that zinc regulation of gene expression is cell-type specific, and MT genes play important roles in prostate malignancy.     

Temporal study of the activity of matrix metalloproteinases and their endogenous inhibitors during wound healing

The restoration of functional connective tissue is a major goal of the wound healing process. This regenerative event requires the deposition and accumulation of collagenous and noncollagenous matrix molecules as well as the remodelling of extracellular matrix (ECM) by matrix metalloproteinases (MMPs). In this study, we have utilized substrate gel electrophoresis, radiometric enzyme assays, and Western blot analyses to determine the temporal pattern of appearance and activity of active and latent MMPs and their inhibitors during the entire healing process in a partial thickness wound model. Through the use of substrate gel electrophoresis, we studied the appearance of proteolytic bands whose molecular weight was consistent with their being members of the MMP family of enzymes. Proteolytic bands whose molecular weight is consistent with both the active and latent forms of MMP-2 (72 kDa, Type IV gelatinase) were detected in wound fluid of days 1–7 after wounding. The number of active MMP-2 species detectable in wound fluid was greatest during days 4–6 after wounding. The most prominent proteolytic band detected each day migrated with a molecular weight consistent with it being the latent form of MMP-9 (92 kDa, Type V pro-collagenase). In contrast to MMP-2, the active form of this enzyme was never detected. The presence of MMP-1 (interstitial collagenase) was detected by immunoblot in the wound fluid from days 1–6 post-injury. Using a radiometric enzyme assay for collagenase inhibitory activity we have also determined the time course of activity of endogenous matrix metalloproteinase inhibitors. We have correlated these data to the known cellular events occurring in the wound during this time period as well. This study establishes a prototypical pattern of MMP appearance in normal wound healing. It may also provide potential intervention sites for the therapeutic use of inhibitors of aberrant MMP activities which characterize chronic wounds. © 1996 Wiley-Liss, Inc.     

Cellular and molecular facets of keratinocyte reepithelization during wound healing

Cutaneous wound healing is a highly coordinated physiological process that rapidly and efficiently restores skin integrity. Reepithelization is a crucial step during wound healing, which involves migration and proliferation of keratinocytes to cover the denuded dermal surface. Recent advances in wound biology clarified the molecular pathways governing keratinocyte reepithelization at wound sites. These new findings point towards novel therapeutic targets and provide suitable methods to promote faster tissue regeneration in vivo.     

Cytophotometric study of blood neutrophil and wound exudate myeloperoxidase in experimental wound healing

Changes in the activity of blood neutrophil and wound exudate myeloperoxidase (MP) have been studied cytophotometrically on the models of aseptic and infected experimental wounds in 220 male Wistar rats on the 1st-10th, 12th and 15th day after wounding. It has been established that changes in MP activity reflect the nature and stages of the pathological process and the animals' reaction to it. MP activity is significantly higher in animals with infected wounds, which indicates the intensity and duration of the inflammatory process and is of prognostic value.