Different types of ROS-scavenging enzymes are expressed during cutaneous wound repair

Wound healing activity of a collagen-derived cryptic peptide

Wound healing involves a well-controlled series of interactions among cells and several mediators leading to the restoration of damaged tissue. Degradation of the extracellular matrix (ECM) protein collagen during remodelling of wound tissue leads to the release of bioactive peptides that can possibly influence the healing process. The RGD-containing, antioxidative collagen peptide E1 isolated in an earlier work was screened in this study for its ability to influence multiple steps of the wound healing process. E1 was assayed for and found to be chemotactic. Excision and incision wounds were created on separate groups of rats and E1 was administered topically. The wound tissues were isolated on the 4th and 8th days post-wound and subjected to biochemical and biophysical analysis. A significant decrease in lipid peroxides in the treatment group confirmed the in vivo antioxidant capacity of E1. The treatment group also displayed significant increase in total protein, collagen and amino sugar synthesis indicating faster ECM formation. The significantly increased rate of wound contraction and reepithelialisation along with higher tensile strength of the wound tissue corroborated the results of biochemical analysis. The results confirm the significant role played by collagen peptides in accelerating the healing process and justify their possible use as a pharmaceutical agent.

PLGA nanofiber membranes loaded with epigallocatechin-3-O-gallate are beneficial to prevention of postsurgical adhesions

This study concentrates on the development of biodegradable nanofiber membranes with controlled drug release to ensure reduced tissue adhesion and accelerated healing. Nanofibers of poly(lactic-co-glycolic acid) (PLGA) loaded with epigallocatechin-3-O-gallate (EGCG), the most bioactive polyphenolic compound in green tea, were electrospun. The physicochemical and biomechanical properties of EGCG-releasing PLGA (E-PLGA) nanofiber membranes were characterized by atomic force microscopy, EGCG release and degradation profiles, and tensile testing. In vitro antioxidant activity and hemocompatibility were evaluated by measuring scavenged reactive oxygen species levels and activated partial thromboplastin time, respectively. In vivo antiadhesion efficacy was examined on the rat peritonea with a surgical incision. The average fiber diameter of E-PLGA membranes was approximately 300–500 nm, which was almost similar to that of pure PLGA equivalents. E-PLGA membranes showed sustained EGCG release mediated by controlled diffusion and PLGA degradation over 28 days. EGCG did not adversely affect the tensile strength of PLGA membranes, whereas it significantly decreased the elastic modulus and increased the strain at break. E-PLGA membranes were significantly effective in both scavenging reactive oxygen species and extending activated partial thromboplastin time. Macroscopic observation after 1 week of surgical treatment revealed that the antiadhesion efficacy of E-PLGA nanofiber membranes was significantly superior to those of untreated controls and pure PLGA equivalents, which was comparable to that of a commercial tissue-adhesion barrier. In conclusion, the E-PLGA hybrid nanofiber can be exploited to craft strategies for the prevention of postsurgical adhesions.

Polarity of extracts and fractions of four Combretum (Combretaceae) species used to treat infections and gastrointestinal disorders in southern African traditional medicine has a major effect on different relevant in vitro activities

ETHNOPHARMACOLOGICAL IMPORTANCE

Gastrointestinal disorders and infections are the major pathoaetiologies of diarrhoea causing many problems in human health and animal production. Many Combretum species are used in traditional medicine to treat infectious diseases including diarrhoea and many other ailments by rural people in Africa and Asia. Much of the work done to date on this genus was on the non-polar or intermediate polarity components. Some parameters that may cause diarrhoea and the evaluation of more polar extracts have apparently not been investigated.

AIMS

The polar components were extracted and fractionated by solvent-solvent fractionation to yield fractions with different polarities. The activity of these fractions on different parameters that could be involved in factors associated with diarrhoea was investigated. The cytotoxic activities of the extracts were also determined to evaluate the potential of these extracts to combat diarrhoea in production animals.

MATERIALS AND METHODS

Phenolic-enriched leaf extracts of Combretum bracteosum (COB), Combretum padoides (COP), Combretum vendae (COV) and Combretum woodii (COW) were obtained by extracting with a mixture of 70% acetone acidified with 1% HCl and n-hexane. Acetone was removed from a portion of the 70% acetone extract and it was sequentially treated by solvent-solvent fractionation with dichloromethane, ethyl acetate, and butanol to yield fractions with a large variation in polarity. The phenolic constituents of the extracts and fractions were determined using standard procedures The antioxidant activities were determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH); 2,2'-azino-bis (3-ethylbenzothiazoline)-6-sulphonic acid (ABTS(+)) radical scavenging, ferric reducing antioxidant power (FRAP) methods and lipid peroxidation inhibitory capacity standard methods. The ferric reducing antioxidant activities of the fractions were also determined. The minimum inhibitory concentrations (MICs) of the crude extracts and fractions against four bacterial and three fungal strains were assessed with a microplate serial dilution method. Cyclooxygenase (COX) and lipoxygenase (LOX) enzyme inhibitory assays and cytotoxicity studies against Vero cells were also carried out.

RESULT

Some of the fractions had much higher antioxidant activity than the positive controls. The average EC50 values of the extracts for the DPPH and ABTS antioxidant assays were 0.21-12µg/ml (COP), 0.25-16µg/ml (COV), 0.33-9.41µg/ml (COW) and 4.97-85µg/ml (COB) respectively while the mean EC50 values for the positive controls ascorbic acid and trolox were 1.28-1.51 and 1.02-1.19µg/ml respectively. All the crude extracts inhibited lipid peroxidation of linoleic acid by more than 80% at a concentration of 64 µg/ml. COP had the highest antibacterial activity with MICs ranging between 19-2500µg/ml, followed by COV with MICs ranging between 39-625µg/ml; COW and COB had similar MICs ranging between 39-2500µg/ml. COP also had the highest antifungal activity with MICs between 19-625µg/ml. The MIC for COW and COV ranged from 19 to 1250 µg/ml. COB had the lowest antifungal activity (MIC values were between 39 and 625 µg/ml). In general non-polar fractions had a high antimicrobial activity and polar fractions had a high antioxidant activity. The extracts had no activity against COX 1 and 2 enzymes in the anti-inflammatory assay but had good lipoxygenase inhibition. The crude extracts had high concentration of hydrolysable tannin (gallotannin). A good correlation (R(2)= 0.99) was found between the antioxidant activity and total tannin content indicating that, gallotannins may be responsible for the antioxidant activity.

CONCLUSION

The results obtained in this study with more polar extracts indicate that the use of extracts of these plant species as antidiarrhoeal agents may have a scientific basis. The extractant used here extracted a much higher percentage of the phytochemicals than acetone. It was better for isolating antioxidant compounds (polar) but not good for isolating antimicrobial compounds (non-polar) from the same species compared to acetone, ethyl acetate, dichloromethane, and hexane.

Association of heme oxygenase 1 with the restoration of liver function after damage in murine malaria by Plasmodium yoelii

The liver efficiently restores function after damage induced during malarial infection once the parasites are cleared from the blood. However, the molecular events leading to the restoration of liver function after malaria are still obscure. To study this, we developed a suitable model wherein mice infected with Plasmodium yoelii (45% parasitemia) were treated with the antimalarial α/β-arteether to clear parasites from the blood and, subsequently, restoration of liver function was monitored. Liver function tests clearly indicated that complete recovery of liver function occurred after 25 days of parasite clearance. Analyses of proinflammatory gene expression and neutrophil infiltration further indicated that hepatic inflammation, which was induced immediately after parasite clearance from the blood, was gradually reduced. Moreover, the inflammation in the liver after parasite clearance was found to be correlated positively with oxidative stress and hepatocyte apoptosis. We investigated the role of heme oxygenase 1 (HO-1) in the restoration of liver function after malaria because HO-1 normally renders protection against inflammation, oxidative stress, and apoptosis under various pathological conditions. The expression and activity of HO-1 were found to be increased significantly after parasite clearance. We even found that chemical silencing of HO-1 by use of zinc protoporphyrin enhanced inflammation, oxidative stress, hepatocyte apoptosis, and liver injury. In contrast, stimulation of HO-1 by cobalt protoporphyrin alleviated liver inflammation and reduced oxidative stress, hepatocyte apoptosis, and associated tissue injury. Therefore, we propose that selective induction of HO-1 in the liver would be beneficial for the restoration of liver function after parasite clearance.

Gene expression in fetal murine keratinocytes and fibroblasts

BACKGROUND

Early fetuses heal wounds without the formation of a scar. Many studies have attempted to explain this remarkable phenomenon. However, the exact mechanism remains unknown. Herein, we examine the predominant cell types of the epidermis and dermis--the keratinocyte and fibroblast--during different stages of fetal development to better understand the changes that lead to scarring wound repair versus regeneration.

MATERIALS AND METHODS

Keratinocytes and fibroblasts were harvested and cultured from the dorsal skin of time-dated BALB/c fetuses. Total RNA was isolated and microarray analysis was performed using chips with 42,000 genes. Significance analysis of microarrays was used to select genes with >2-fold expression differences with a false discovery rate<2. Enrichment analysis was performed on significant genes to identify differentially expressed pathways.

RESULTS

By comparing the gene expression profile of keratinocytes from E16 versus E18 fetuses, we identified 24 genes that were downregulated at E16. Analysis of E16 and E18 fibroblasts revealed 522 differentially expressed genes. Enrichment analysis showed the top 20 signaling pathways that were downregulated in E16 keratinocytes and upregulated or downregulated in E16 fibroblasts.

CONCLUSIONS

Our data reveal 546 differentially expressed genes in keratinocytes and fibroblasts between the scarless and scarring transition. In addition, a total of 60 signaling pathways have been identified to be either upregulated or downregulated in these cell types. The genes and pathways recognized by our study may prove to be essential targets that may discriminate between fetal wound regeneration and adult wound repair.

Hypertrophic Scar Formation on Application of Terpenoid Fraction of Tuberous Root of Mirabilis jalapa L. on Excision Wound Model in Wistar Albino Rats

The study was designed to evaluate the effects of hydromethanolic extract of tuberous root of M. jalapa and its terpenoid and flavonoid fractions on cutaneous wound healing in Wistar Albino rats. The hydromethanolic extract was subfractionated by sequential extraction in solvents (moderately nonpolar to polar). The extract and its (terpenoid and flavonoid) fractions were used for cutaneous wound healing studies by using excision wound model on rat. Their effects on wound contraction rate, biochemical and histological changes, and expression of growth factors such as collagen 3A, basic fibroblast growth factor, and vascular endothelial growth factor were investigated. The results indicated that flavonoid treated group showed significant decrease (P < 0.05) in antioxidant enzyme level as compared to control in wound healing process, whereas terpenoid fraction showed significant increase (P < 0.05) in expression of growth factor levels but regeneration and remodeling stages were delayed due to formation of thicker ulcus layer and also there were no hair follicle-like blood capillaries formation which ultimately may lead to formation of hypertrophic scar of wound. Therefore, from this study, it can be concluded that terpenoid fraction prolongs proliferation phase and hence may have tendency to convert the wound into hypertrophic wound.

Extracellular glutathione promotes migration of hydrogen peroxide-stressed cultured chick embryonic skin cells

The ability of glutathione to affect melanocyte survival has fostered its use in a variety of applications related to epithelial cells. Our study focused on fibroblast migration and the effects of oxidative stress. We used scratch assays to measure cell migration: fibroblasts were harvested from embryonic chicks, grown to confluence in a monolayer, and the layer was scratched to initiate migration. Migration rates were measured over 8 h using photomicrographs, and vinculin expression as an indicator focal adhesion formation was measured using immunofluorescence. Addition of 200 μM glutathione to the culture media in which the cells grew resulted in a significantly increased rate of scratch closure. When the scratch assays were performed in the presence of 100 μM H2O2 (to simulate oxidative stress), the cells ceased to migrate. Addition of 200 μM glutathione to the H2O2-treated scratched layers resulted in a restoration of the scratch closure capabilities. At the subcellular level, addition of extracellular glutathione resulted in a redistribution of vinculin into fewer but larger aggregates. In cells at the edge of scratched monolayers that were treated with H2O2, vinculin particles were distributed throughout the cell in smaller aggregates; addition of glutathione resulted in vinculin aggregates that were larger and closer to the edges of the cell, indicating that these cells were more migratory. Our results suggest that glutathione promotes fibroblast migration, possibly via a mechanism that promotes the formation of focal adhesions.

Targeting the redox balance in inflammatory skin conditions

Reactive oxygen species (ROS) can be both beneficial and deleterious. Under normal physiological conditions, ROS production is tightly regulated, and ROS participate in both pathogen defense and cellular signaling. However, insufficient ROS detoxification or ROS overproduction generates oxidative stress, resulting in cellular damage. Oxidative stress has been linked to various inflammatory diseases. Inflammation is an essential response in the protection against injurious insults and thus important at the onset of wound healing. However, hampered resolution of inflammation can result in a chronic, exaggerated response with additional tissue damage. In the pathogenesis of several inflammatory skin conditions, e.g., sunburn and psoriasis, inflammatory-mediated tissue damage is central. The prolonged release of excess ROS in the skin can aggravate inflammatory injury and promote chronic inflammation. The cellular redox balance is therefore tightly regulated by several (enzymatic) antioxidants and pro-oxidants; however, in case of chronic inflammation, the antioxidant system may be depleted, and prolonged oxidative stress occurs. Due to the central role of ROS in inflammatory pathologies, restoring the redox balance forms an innovative therapeutic target in the development of new strategies for treating inflammatory skin conditions. Nevertheless, the clinical use of antioxidant-related therapies is still in its infancy.

Efficacy of L-proline administration on the early responses during cutaneous wound healing in rats

Proline (Pro) plays a versatile role in cell metabolism and physiology. Pro and hydroxypro are major imino acids present in collagen, an important connective tissue protein, essential for wound healing, which is a primary response to tissue injury. This study explains the role of L-pro on cutaneous wound healing in rats when administered both topically and orally. Open excision wounds were made on the back of rats, and 200 μl (200 mg) of pro was administered topically and orally once daily to the experimental rats until the wounds healed completely. The control wounds were left untreated. Granulation tissues formed were removed after day 4 and 8 of post excision wounding, and biochemical parameters such as total protein, collagen, hexosamine, and uronic acid were estimated. Levels of enzymatic and non-enzymatic antioxidants such as catalase, superoxide dismutase, glutathione peroxidase, ascorbic acid, and reduced glutathione were evaluated along with lipid peroxides in the granulation tissues. Tensile strength and period of epithelialization were also measured. It was observed that the treated wounds healed very fast as evidenced by augmented rates of epithelialization and wound contraction, which was also confirmed by histological examinations. The results strappingly authenticate the beneficial effects of the topical administration of L-proline in the acceleration of wound healing than the oral administration and control.

Decreased skin-mediated detoxification contributes to oxidative stress and insulin resistance

The skin, the body's largest organ, plays an important role in the biotransformation/detoxification and elimination of xenobiotics and endogenous toxic substances, but its role in oxidative stress and insulin resistance is unclear. We investigated the relationship between skin detoxification and oxidative stress/insulin resistance by examining burn-induced changes in nicotinamide degradation. Rats were divided into four groups: sham-operated, sham-nicotinamide, burn, and burn-nicotinamide. Rats received an intraperitoneal glucose injection (2 g/kg) with (sham-nicotinamide and burn-nicotinamide groups) or without (sham-operated and burn groups) coadministration of nicotinamide (100 mg/kg). The results showed that the mRNA of all detoxification-related enzymes tested was detected in sham-operated skin but not in burned skin. The clearance of nicotinamide and N¹-methylnicotinamide in burned rats was significantly decreased compared with that in sham-operated rats. After glucose loading, burn group showed significantly higher plasma insulin levels with a lower muscle glycogen level than that of sham-operated and sham-nicotinamide groups, although there were no significant differences in blood glucose levels over time between groups. More profound changes in plasma H₂O₂ and insulin levels were observed in burn-nicotinamide group. It may be concluded that decreased skin detoxification may increase the risk for oxidative stress and insulin resistance.

Heme oxygenase, inflammation, and fibrosis: the good, the bad, and the ugly?

Upon injury, prolonged inflammation and oxidative stress may cause pathological wound healing and fibrosis, leading to formation of excessive scar tissue. Fibrogenesis can occur in most organs and tissues and may ultimately lead to organ dysfunction and failure. The underlying mechanisms of pathological wound healing still remain unclear, and are considered to be multifactorial, but so far, no efficient anti-fibrotic therapies exist. Extra- and intracellular levels of free heme may be increased in a variety of pathological conditions due to release from hemoproteins. Free heme possesses pro-inflammatory and oxidative properties, and may act as a danger signal. Effects of free heme may be counteracted by heme-binding proteins or by heme degradation. Heme is degraded by heme oxygenase (HO) that exists as two isoforms: inducible HO-1 and constitutively expressed HO-2. HO generates the effector molecules biliverdin/bilirubin, carbon monoxide, and free iron/ferritin. HO deficiency in mouse and man leads to exaggerated inflammation following mild insults, and accumulating epidemiological and preclinical studies support the widely recognized notion of the cytoprotective, anti-oxidative, and anti-inflammatory effects of the activity of the HO system and its effector molecules. In this review, we address the potential effects of targeted HO-1 induction or administration of HO-effector molecules as therapeutic targets in fibrotic conditions to counteract inflammatory and oxidative insults. This is exemplified by various clinically relevant conditions, such as hypertrophic scarring, chronic inflammatory liver disease, chronic pancreatitis, and chronic graft rejection in transplantation.

The skin function: a factor of anti-metabolic syndrome

The body's total antioxidant capacity represents a sum of the antioxidant capacity of various tissues/organs. A decrease in the body's antioxidant capacity may induce oxidative stress and subsequent metabolic syndrome, a clustering of risk factors for type 2 diabetes and cardiovascular disease. The skin, the largest organ of the body, is one of the major components of the body's total antioxidant defense system, primarily through its xenobiotic/drug biotransformation system, reactive oxygen species-scavenging system, and sweat glands- and sebaceous glands-mediated excretion system. Notably, unlike other contributors, the skin contribution is variable, depending on lifestyles and ambient temperature or seasonal variations. Emerging evidence suggests that decreased skin's antioxidant and excretory functions (e.g., due to sedentary lifestyles and low ambient temperature) may increase the risk for metabolic syndrome. This review focuses on the relationship between the variability of skin-mediated detoxification and elimination of exogenous and endogenous toxic substances and the development of metabolic syndrome. The potential role of sebum secretion in lipid and cholesterol homeostasis and its impact on metabolic syndrome, and the association between skin disorders (acanthosis nigricans, acne, and burn) and metabolic syndrome are also discussed.

Oxidation of Akt2 kinase promotes cell migration and regulates G1-S transition in the cell cycle

Phosphorylation has long been recognized as the key mediator of protein signaling. New modes of signaling regulation are emerging with the development of specific chemical probes and application of high-throughput mass spectrometry technologies. Using biotin-tagged chemical probes for protein oxidation, mass spectrometry and functional assays, our group has recently reported isoform-specific oxidation of Akt2 in response to PDGF signaling. The studies included here investigate the functional consequence of oxidation on Akt2-mediated cell migration and cell cycle. Akt2-KO MEFs transduced with WT and Cys124Ser Akt2 were used as the model system for these studies. The implications of these findings on disease pathology are discussed.

Glucose Oxidase Incorporated Collagen Matrices for Dermal Wound Repair in Diabetic Rat Models: A Biochemical Study

Impaired wound healing in diabetes is a well-documented phenomenon. Emerging data favor the involvement of free radicals in the pathogenesis of diabetic wound healing. We investigated the beneficial role of the sustained release of reactive oxygen species (ROS) in diabetic dermal wound healing. In order to achieve the sustained delivery of ROS in the wound bed, we have incorporated glucose oxidase in the collagen matrix (GOIC), which is applied to the healing diabetic wound. Our in vitro proteolysis studies on incorporated GOIC show increased stability against the proteases in the collagen matrix. In this study, GOIC film and collagen film (CF) are used as dressing material on the wound of streptozotocin-induced diabetic rats. A significant increase in ROS ( p < 0.05) was observed in the fibroblast of GOIC group during the inflammation period compared to the CF and control groups. This elevated level up regulated the antioxidant status in the granulation tissue and improved cellular proliferation in the GOIC group. Interestingly, our biochemical parameters nitric oxide, hydroxyproline, uronic acid, protein, and DNA content in the healing wound showed that there is an increase in proliferation of cells in GOIC when compared to the control and CF groups. In addition, evidence from wound contraction and histology reveals faster healing in the GOIC group. Our observations document that GOIC matrices could be effectively used for diabetic wound healing therapy.

Characterization of Deinococcus radiophilus thioredoxin reductase active with both NADH and NADPH

Thioredoxin reductase (TrxR, EC 1.6.4.5) of Deinococcus radiophilus was purified by steps of sonication, ammonium sulfate fractionation, 2'5' ADP Sepharose 4B affinity chromatography, and Sephadex G-100 gel filtration. The purified TrxR, which was active with both NADPH and NADH, gave a 368 U/mg protein of specific activity with 478-fold purification and 18% recovery from the cell-free extract. An isoelectric point of the purified enzymes was ca. 4.5. The molecular weights of the purified TrxR estimated by PAGE and gel filtration were about 63.1 and 72.2 kDa, respectively. The molecular mass of a TrxR subunit is 37 kDa. This suggests that TrxR definitely belongs to low molecular weight TrxR (L-TrxR). The Km and Vmax of TrxR for NADPH are 12.5 μM and 25 μM/min, whereas those for NADH are 30.2 μM and 192 μM/min. The Km and Vmax for 5, 5'-dithio-bis-2-nitrobenzoic acid (DTNB, a substituted substrate for thioredoxin) are 463 μM and 756 μM/min, respectively. The presence of FAD in TrxR was confirmed with the absorbance peaks at 385 and 460 nm. The purified TrxR was quite stable from pH 3 to 9, and was thermo-stable up to 70°C. TrxR activity was drastically reduced (ca. 70%) by Cu(2+), Zn(2+), Hg(2+), and Cd(2+), but moderately reduced (ca. 50%) by Ag(+). A significant inhibition of TrxR by N-ethylmaleimide suggests an occurrence of cysteine at its active sites. Amino acid sequences at the N-terminus of purified TrxR are H(2)N-Ser-Glu-Gln-Ala-Gln-Met-Tyr-Asp-Val-Ile-Ile-Val-Gly-Gly-Gly-Pro-Ala-Gly-Leu-Thr-Ala-COOH. These sequences show high similarity with TrxRs reported in Archaea, such as Methanosarcina mazei, Archaeoglobus fulgidus etc.

Regulation of lung cancer cell migration and invasion by reactive oxygen species and caveolin-1

The acquired capability of tumor cells to migrate and invade neighboring tissues is associated with high metastatic potential and advanced stage of cancers. Recently, signaling molecules such as reactive oxygen species (ROS) and caveolin-1 (Cav-1) have been implicated in the aggressive behavior of cancer cells. However, the roles of specific ROS in cancer cell migration and Cav-1 regulation are unclear. We demonstrate here that Cav-1 plays an important role in the migration and invasion of human lung carcinoma H460 cells and that these effects are differentially regulated by cellular ROS. Using various known inhibitors and donors of ROS, we found that different ROS have different effects on Cav-1 expression and cell migration and invasion. Superoxide anion and hydrogen peroxide down-regulated Cav-1 expression and inhibited cell migration and invasion, whereas hydroxyl radical up-regulated the Cav-1 expression and promoted cell migration and invasion. The down-regulating effect of superoxide anion and hydrogen peroxide on Cav-1 is mediated through a transcription-independent mechanism that involves protein degradation via the ubiquitin-proteasome pathway. These results indicate the essential role of different ROS in cancer cell motility and through Cav-1 expression, which may provide a key mechanism controlling tumor progression and metastasis. The up-regulation of Cav-1 and cell motility by hydroxyl free radical suggests an important role of this ROS as a positive regulator of tumor progression.

Cell resilience in species life spans: a link to inflammation?

Species differences in life span have been attributed to cellular survival during various stressors, designated here as 'cell resilience'. In primary fibroblast cultures, cell resilience during exposure to free radicals, hypoglycemia, hyperthermia, and various toxins has shown generally consistent correlations with the species characteristic life spans of birds and mammals. However, the mechanistic links of cell resilience in fibroblast cultures to different species life spans are poorly understood. We propose that certain experimental stressors are relevant to somatic damage in vivo during inflammatory responses of innate immunity, particularly, resistance to reactive oxygen species (ROS), low glucose, and hyperthermia. According to this hypothesis, somatic cell resilience determines species differences in longevity during repeated infections and traumatic injuries in the natural environment. Infections and injury expose local fibroblasts and other cells to ROS generated by macrophages and to local temperature elevations. Systemically, acute phase immune reactions cause hypoglycemia and hyperthermia. We propose that cell resilience to somatic stressors incurred in inflammation is important in the evolution of longevity and that longer-lived species are specifically more resistant to immune-related stressors. This hypothesis further specifies Kirkwood's disposable soma theory. We suggest expanding the battery of stressors and markers used for comparative studies to additional cell types and additional parameters relevant to host defense and to their ecological specificities.

Redox control of the cell cycle in health and disease

The cellular oxidation and reduction (redox) environment is influenced by the production and removal of reactive oxygen species (ROS). In recent years, several reports support the hypothesis that cellular ROS levels could function as ''second messengers'' regulating numerous cellular processes, including proliferation. Periodic oscillations in the cellular redox environment, a redox cycle, regulate cell-cycle progression from quiescence (G(0)) to proliferation (G(1), S, G(2), and M) and back to quiescence. A loss in the redox control of the cell cycle could lead to aberrant proliferation, a hallmark of various human pathologies. This review discusses the literature that supports the concept of a redox cycle controlling the mammalian cell cycle, with an emphasis on how this control relates to proliferative disorders including cancer, wound healing, fibrosis, cardiovascular diseases, diabetes, and neurodegenerative diseases. We hypothesize that reestablishing the redox control of the cell cycle by manipulating the cellular redox environment could improve many aspects of the proliferative disorders.

Antioxidant effects of mycophenolate mofetil in a murine pleurisy model

Generation of oxidative stress induced by reactive oxygen species (ROS) and nitrogen (RNS) is believed to be a primary factor in the etiology of various inflammatory diseases. Although, the process of generation of oxygen species is a physiological event, in the inflammatory process this event is increased and produces large amounts of reactive species that leads to lipid peroxidation and to cell death. Mycophenolate mofetil (MMF) is a drug effective in protecting against chronic allograft failure and recently was introduced as an alternative for the treatment of various inflammatory diseases such as glomerulopathies, systemic lupus erythematosus and systemic vasculitis. Based on studies of the anti-inflammatory effect of MMF the aim of this study was to evaluate the effects of MMF on the inhibition of leukocytes and exudation, as well as myeloperoxidase and some antioxidant enzyme activities using carrageenan-induced pleurisy in mice. Our results showed that MMF significantly decreased leukocyte influx (P<0.01), exudation (P<0.01), superoxide dismutase (P<0.05), catalase (P<0.05), glutathione peroxidase (P<0.01), glutathione S-transferase (P<0.01) activities, levels of lipid peroxidation (P<0.05), as well as myeloperoxidase activity (P<0.05) on both phases (4h and 48h) of the inflammatory response induced by carrageenan into the mice pleural cavity. In conclusion, the anti-inflammatory effect of MMF may be, at least in part, via inhibition of ROS and/or NRS overgeneration, and consequently, attenuating the related oxidative stress.

Erythropoietin Stimulates Wound Healing and Angiogenesis in Mice

Erythropoietin exerts hematopoietic effects by stimulating proliferation of early erythroid precursors. Nonhematopoietic effects of erythropoietin have also been shown. It may act as a new angiogenic factor in wound healing. This study aimed to investigate the effect of systemic administration of recombinant human erythropoietin on wound healing in mice. Dorsal incisional wounds were performed in mice, which were then divided into two groups; a group treated for 7 days with recombinant human erythropoietin, and a control group. Sacrificing animals on day 7, the wound tissues were collected for analysis of wound breaking strength, malondialdehyde, a marker of lipid peroxidation, hydroxyproline, an index of reparative collagen deposition, reduced glutathione levels, and for histological evaluation. The immunohistochemical determination of vascular endothelial growth factor (VEGF) which is believed to be the most prevalent angiogenic factor throughout the skin repair process, was also studied. The treatment significantly increased wound breaking strength by decreasing malondialdehyde and increasing hydroxyproline levels on day 7 after wounding. No statistically meaningful change was observed in reduced glutathione content. VEGF was immunostained significantly more on wound tissue of treated animals compared to the control group. Recombinant human erythropoietin treatment may be effective in wound healing due to inhibition of lipid peroxidation, deposition of collagen, and VEGF expression in wound area.

Overexpression of manganese superoxide dismutase in human dermal fibroblasts enhances the contraction of free floating collagen lattice: implications for ageing and hyperplastic scar formation

Cell-matrix interactions are of significant importance for tissue homeostasis of the skin and, if disturbed, may lead to ageing and hyperplastic scar formation. We have studied fibroblasts stably overexpressing manganese superoxide dismutase (MnSOD) with a defined capacity for the removal of superoxide anions and concomitant accumulation of hydrogen peroxide to evaluate the role of enhanced MnSOD activity on the dynamics of cell-matrix interactions in the three-dimensional collagen lattice contraction assay. MnSOD overexpressing fibroblast populated collagen lattices revealed a significantly enhanced contraction compared to collagen lattices populated with vector control cells. The enhanced collagen lattice contraction was in part due to an increase in active TGF-beta1 and the accumulation of H2O2 in MnSOD overexpressing fibroblasts populated collagen lattices. Inhibition of TGF-beta1 signalling by the ALK4,5,7 kinases' inhibitor SB431542 at least partly inhibited the enhanced collagen lattice contraction of MnSOD overexpressing fibroblasts populated lattices. In addition, supplementation of vector control fibroblast populated collagen lattices with recombinant TGF-beta1 concentration dependently enhanced the collagen lattice contraction. In the presence of the antioxidant Ebselen, a mimic of H2O2 and other hydroperoxides/peroxynitrite-detoxifying glutathione peroxidase, collagen lattice contraction and the activation of TGF-beta1 were significantly reduced in collagen lattices populated with MnSOD overexpressing fibroblasts. Collectively, these data suggest that H2O2 or other hydroperoxides or peroxynitrite or a combination thereof may function as important second messengers in collagen lattice contraction and act at least in part via TGF-beta1 activation.

Fibroblast dysfunction is a key factor in the non-healing of chronic venous leg ulcers

Chronic age-related degenerative disorders, including the formation of chronic leg wounds, may occur due to aging of the stromal tissues and ensuing dysfunctional cellular responses. This study investigated the impact of environmental-driven cellular aging on wound healing by conducting a comprehensive analysis of chronic wound fibroblast (CWF) behavior in comparison with patient-matched healthy skin normal fibroblasts (NF). The dysfunctional wound healing abilities of CWF correlated with a significantly reduced proliferative life span and early onset of senescence compared with NF. However, pair-wise comparisons of telomere dynamics between NF and CWF indicated that the induction of senescence in CWF was telomere-independent. Microarray and functional analysis suggested that CWFs have a decreased ability to withstand oxidative stress, which may explain why these cells prematurely senescence. Microarray analysis revealed lower expression levels of several CXC chemokine genes (CXCL-1, -2, -3, -5, -6, -12) in CWF compared with NF (confirmed by ELISA). Functionally, this was related to impaired neutrophil chemotaxis in response to CWF-conditioned medium. Although the persistence of non-healing wounds is, in part, due to prolonged chronic inflammation and bacterial infection, our investigations show that premature fibroblast aging and an inability to correctly express a stromal address code are also implicated in the disease chronicity.

Evaluation of antimicrobial, antioxidant and wound-healing potentials of Holoptelea integrifolia

The methanolic extracts of Holoptelea integrifolia (Roxb.) (Urticaceae) leaves (MLE) and stem bark (MSBE) were studied for the wound-healing potential. Since wound healing is severely hampered by microbial infection and reactive oxygen species (ROS), this study was undertaken to evaluate antimicrobial and antioxidant activity apart from wound-healing activity. The antimicrobial property of the Holoptelea was studied against the six bacterial and five fungal strains using the agar well diffusion method and minimum microbicidal concentration and minimum inhibitory concentration were determined for each strain, in which methanolic extract of stem bark (MSBE) has shown bigger zone of inhibition (11.3-20.4 mm) than methanolic extract of leaves (MLE) (9.6-14.9 mm). The anti-oxidant activity was evaluated by DPPH free radical scavenging activity using HPLC method. The IC(50) values obtained for MSBE (TPC: 78.53+/-1.26 mg/g) and MLE (TPC: 57.71+/-1.45 mg/g) were 37.66+/-0.48 and 50.36+/-0.59 microg/well, respectively. In excision wound model, more than 90% wound healing was recorded in treated groups by 14 days of post surgery, where as only 62.99% was observed in the control group. In incision model, higher breaking strengths and higher hydroxyproline content in treated groups suggested higher collagen re-deposition than the control group. Finally, histopathology studies conformed wound-healing activity of Holoptelea integrifolia.

Peroxiredoxin 6 is required for blood vessel integrity in wounded skin

Peroxiredoxin 6 (Prdx6) is a cytoprotective enzyme with largely unknown in vivo functions. Here, we use Prdx6 knockout mice to determine its role in UV protection and wound healing. UV-mediated keratinocyte apoptosis is enhanced in Prdx6-deficient mice. Upon skin injury, we observe a severe hemorrhage in the granulation tissue of knockout animals, which correlates with the extent of oxidative stress. At the ultrastructural level endothelial cells appear highly damaged, and their rate of apoptosis is enhanced. Knock-down of Prdx6 in cultured endothelial cells also increases their susceptibility to oxidative stress, thus confirming the sensitivity of this cell type to loss of Prdx6. Wound healing studies in bone marrow chimeric mice demonstrate that Prdx6-deficient inflammatory and endothelial cells contribute to the hemorrhage phenotype. These results provide insight into the cross-talk between hematopoietic and resident cells at the wound site and the role of reactive oxygen species in this interplay.

Activity of antioxidant enzymes in the skin during surgical wounds

Full-thickness skin wounds (460 mm(2)) in rats were associated with increased blood chemiluminescence and neutrophil infiltration of the wound tissue and surrounding skin (recorded by myeloperoxidase activity). Activities of glutathione peroxidase and glutathione S-transferase in the skin and wound tissue increased on days 4 and 8. A correlation was revealed between activities of these enzymes and myeloperoxidase activity. Activities of myeloperoxidase and catalase increased in patient's skin excised during plastic surgeries of more than 2.5 h duration.

Cationized catalase-loaded hydrogel for growth inhibition of peritoneally disseminated tumor cells

A previous study demonstrated that ethylenediamine-conjugated catalase (ED-catalase) inhibits peritoneal dissemination of tumor cells in mice. To increase its inhibitory effects by sustained release, a hydrogel formulation of ED-catalase was prepared using a biodegradable hydrogel consisting of an acidic gelatin with an isoelectric point of 5.0. Although intraperitoneally injected ED-catalase solution rapidly disappeared from the cavity, more than 10% of ED-catalase remained even at 14 days after implantation of ED-catalase/hydrogel into the cavity. Then, the effect of ED-catalase/hydrogel on peritoneal dissemination of tumor cells was evaluated by measuring the luciferase activity of abdominal organs after intraperitoneal inoculation of colon26/Luc, a colon adenocarcinoma stably expressing luciferase. ED-catalase/hydrogel showed a significantly (P<0.05) greater effect on inhibiting the growth of tumor cells than ED-catalase solution, demonstrating the importance of the retention of ED-catalase within the cavity as far as inhibition is concerned. Serial in vivo images of luciferase activity revealed that the ED-catalase/hydrogel significantly (P<0.05) retarded the growth rate of tumor cells. Survival of tumor-bearing mice supported the findings obtained with the luminescence-based analyses. These findings indicate that the sustained release of ED-catalase from hydrogels into the cavity is highly effective in inhibiting the growth of peritoneally disseminated tumor cells.

Reactive oxygen species and their detoxification in healing skin wounds

Injury to the skin initiates a cascade of events, which finally lead to at least partial reconstruction of the wounded tissue. The wound-healing process has been well described at the histological level, but the underlying molecular mechanisms are still poorly defined. To gain insight into these mechanisms we searched for genes, which are regulated by skin injury. Interestingly, some of the genes that we identified encode cytoprotective proteins, in particular enzymes, which detoxify reactive oxygen species (ROS). Since ROS are produced in high amounts at the wound site as a defense against invading bacteria, the expression of these genes is most likely important for the protection of cells against these toxic molecules. In this review, we summarize the results on the expression of cytoprotective genes in wounded skin, and we discuss their possible roles in the wound-healing process.

Peroxiredoxin 6 is a potent cytoprotective enzyme in the epidermis

Peroxiredoxin 6 is an enzyme that detoxifies hydrogen peroxide and various organic peroxides. In previous studies we found strongly increased expression of peroxiredoxin 6 in the hyperproliferative epidermis of wounded and psoriatic skin, suggesting a role of this enzyme in epidermal homeostasis. To address this question, we generated transgenic mice overexpressing peroxiredoxin 6 in the epidermis. Cultured keratinocytes from transgenic mice showed enhanced resistance to the toxicity of various agents that induce oxidative stress. However, overexpression of peroxiredoxin 6 did not affect skin morphogenesis or homeostasis. On skin injury, enhancement of wound closure was observed in aged animals. Most importantly, peroxiredoxin 6 overexpression strongly reduced the number of apoptotic cells after UVA or UVB irradiation. These findings demonstrate that peroxiredoxin 6 protects keratinocytes from cell death induced by reactive oxygen species in vitro and in vivo, suggesting that activation of this enzyme could be a novel strategy for skin protection under stress conditions.

Inhibition of the TPA-induced cutaneous inflammation and hyperplasia by EC-SOD

This study reports the roles of extracellular superoxide dismutase (EC-SOD) in the cutaneous inflammation and hyperplasia with 12-O-tetradecanoylphorbol-3-acetate (TPA) application in EC-SOD transgenic mice (Tg EC-SOD). Topical double TPA treatment induced the various inflammatory changes including the epidermal thickness, elevated the PCNA-labeling index, the edema formation, and increased production of hydrogen peroxide (H2O2) in wild type mice (WT). These changes were markedly suppressed in TPA-treated Tg EC-SOD. The expressions of the inflammatory cytokines, IL-1alpha and IL-1beta, were reduced in the TPA-treated Tg EC-SOD compared with those in TPA-treated WT. The expression of IL-1alpha was significantly increased in the skin of TPA-treated WT, especially in the basal and suprabasal layers, but it was restricted focally in basal layer of the skin of TPA-treated Tg EC-SOD. The number of infiltrating inflammatory cells and the IL-1beta expressing cells was obviously reduced in TPA-treated Tg EC-SOD in comparison with TPA-treated WT. The result suggests that EC-SOD might play an important role in the suppression of TPA-induced cutaneous inflammation and epidermal hyperplasia by regulating the expression of IL-1alpha and IL-1beta, although the mechanisms remain to be elucidated.

Oxidative stress in chronic venous leg ulcers

Venous leg ulcers are common and cause considerable morbidity in the population. As healing may be slow or may never be achieved, ulcers create persistent and substantial demands on clinical resources. Great efforts have been made to accelerate tissue repair in chronic venous leg ulcers with limited success. This may at least be partly due to the limited knowledge on the microenvironment of chronic wounds. In fact, the tremendous impact of the microenvironmental conditions on the outcome of wound healing has increasingly become apparent. Oxidative stress as a consequence of an imbalance in the prooxidant-antioxidant homeostasis in chronic wounds is thought to drive a deleterious sequence of events finally resulting in the nonhealing state. The majority of reactive oxygen species are most likely released by neutrophils and macrophages and to an unknown extent from resident fibroblasts and endothelial cells. As the inflammatory phase does not resolve in chronic wounds, the load of reactive oxygen species persists over a long period of time with subsequent continuous damage and perpetuation of the inflammation. In this article, we will critically discuss recent findings that support the role of oxidative stress in the pathophysiology of nonhealing chronic venous leg ulcers.

Reactive oxygen species scavenging activity during periodontal mucoperiosteal healing: An experimental study in dogs

Excessive release of reactive oxygen species (ROS) in wounded tissue due to inflammation and ischaemia is a deleterious and destructive phenomenon for the healing process. Hence, scavenging of ROS is one of the essential steps in normal wound repair. In this study, we presented a profile of free radical scavenging enzyme (FRSE) activity of periodontal mucoperiosteal wounds in order to investigate ROS activity during periodontal wound healing. Mucoperiosteal periodontal flaps were elevated in the mandibular buccal region of seven dogs between the first premolar and first molar teeth, creating acute incisional wounds in the inner side of the flaps and they were replaced 30 min after elevation. Gingival samples taken from certain biopsy regions at baseline (before flap elevation), day 3, 12, 21 and 30 were processed for detection of active amounts of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX). All enzyme activities had increased by more than 100% of their baseline levels by day 3. SOD activity decreased gradually from days 3 to 30 and reached a level lower than the baseline value. The increase in CAT activity continued until day 21, and decreased to a level higher than the baseline value by day 30. GPX also decreased from day 3, and reached a level less than its baseline value by day 30. Our results suggest that FRSEs may contribute to the detoxification of ROS during periodontal mucoperiosteal healing. This relationship may be utilized to facilitate soft tissue and/or flap management in periodontal or intra-oral treatments.

Pexiganan-incorporated collagen matrices for infected wound-healing processes in rat

The use of peptide-based drugs is limited by their rapid degradability and toxicity at high concentration during their therapeutic application. These problems could be managed by the use of a peptide delivery agent for sustained release in the site of action. Collagen is one of the most proven biomaterials of good biocompatibility with an exceptional ligand encapsulating property. In this work, we have shown that pexiganan, an antimicrobial, 22-amino-acid peptide could be incorporated and delivered to the wound-healing site against bacterial strains Pseudomonas aeruginosa and Staphylococcus aureus. The release profiles of pexiganan collagen films with different collagen concentration were studied. The release of pexiganan from 2.5% w/w of collagen film showed a sustainable activity over 72 h with effective antimicrobial concentrations. Pexiganan-incorporated collagen (PIC)-treated groups were compared with open wound (OW)- and collagen film (CF)-treated rats. PIC-treated animals showed a diminishing level of bacterial growth as compared with OW- and CF-treated animals. The biochemical parameters such as hydroxyproline, protein, DNA, uronic acid, hexosamine, SOD, and catalase content in the granulation tissue of the healing wound revealed increased proliferation of cells involved in tissue reconstruction in PIC-treated groups when compared with OW- and CF-treated groups. Furthermore, spectroscopic studies suggested that collagen structure is not perturbed by pexiganan incorporation. This study provides rationale for application of collagen membrane for antimicrobial peptide delivery in infected wounds.

The role of antioxidants in models of inflammation: Emphasis on l-arginine and arachidonic acid metabolism

Inflammatory processes are made up of a multitude of complex cascades. Under physiological conditions these processes aid in tissue repair. However, under pathophysiological environments, such as wound healing and hypoxia-ischaemia (HI), inflammatory mediators become imbalanced, resulting in tissue destruction. This review addresses the changes in reactive oxygen species (ROS), L-arginine and arachidonic acid metabolism in wound healing and HI and subsequent treatments with promising anti-oxidants. Even though these models may appear divergent, anti-oxidant treatments are nevertheless still having favourable effects. On the basis of recent findings, it is apparent that protection with anti-oxidants is not solely attributed to scavenging of ROS. In addition, the actions of anti-oxidants must be considered in light of the inflammatory process being assessed. To this end, there does not appear to be any universally applicable single mechanism to explain the actions of anti-oxidants.

The effect of finger millet feeding on the early responses during the process of wound healing in diabetic rats

In the present study, the role of finger millet feeding on skin antioxidant status, nerve growth factor (NGF) production and wound healing parameters in healing impaired early diabetic rats is reported. Hyperglycemic rats received food containing 50 g/100 g finger millet (FM). Non-diabetic controls and diabetic controls received balanced nutritive diet. Full-thickness excision skin wounds were made after 2 weeks prior feeding of finger millet diet. The rate of wound contraction, and the levels of collagen, hexosamine and uronic acid in the granulation tissue were determined. The skin antioxidant status and lipid peroxide concentration were also monitored during the study. In hyperglycemic rats fed with finger millet diet, the healing process was hastened with an increased rate of wound contraction. Skin levels of glutathione (GSH), ascorbic acid and alpha-tocopherol in alloxan-induced diabetic rat were lower as compared to non-diabetics. Altered activities of superoxide dismutase (SOD) and catalase (CAT) were also recorded in diabetics. Interestingly, thiobarbituric acid reactive substances (TBARS) were elevated in the wound tissues of all the groups, when compared to normal (unwounded) skin tissues. However, in diabetic rats the TBARS levels of both normal and wounded skin tissues were significantly elevated (P < 0.001) when compared with control (non-diabetic) and diabetics fed with FM. Impaired production of NGF, determined by ELISA, in diabetic rats was improved upon FM feeding and further confirmed by immunocytochemical observations reflects the increased expression of NGF in hyperglycemic rats supplemented with FM-enriched diet. Histological and electron microscopical evaluations revealed the epithelialization, increased synthesis of collagen, activation of fibroblasts and mast cells in FM-fed animals. Thus, increased levels of oxidative stress markers accompanied by decreased levels of antioxidants play a vital role in delaying wound healing in diabetic rats. However, FM feeding to the diabetic animals, for 4 weeks, controlled the glucose levels and improved the antioxidant status, which hastened the dermal wound healing process.

Comparison of oxidative stress biomarker profiles between acute and chronic wound environments

Increasing evidence implicates excessive reactive oxygen species (ROS) generation and ROS-derived degradation products in the pathogenesis of many skin diseases. While numerous attempts have been made to identify prognostic biomarkers of wound healing in skin, these have met with limited success. This study examined the profiles of various oxidative stress biomarkers, namely total protein carbonyl content (from protein oxidation), malondialdehyde content (from lipid peroxidation), and the total antioxidant capacities, in acute wound fluid (n= 10) and chronic wound fluid (n= 12), using a rapid, noninvasive collection technique. Protein carbonyl content was quantified spectrophotometrically and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis/Western blotting, following 2,4-dinitrophenylhydrazine derivitization. Malondialdehyde levels were similarly quantified, following N-methyl-2-phenylindole derivitization. Total antioxidant capacity was determined via wound fluid inhibition of cytochrome C reduction by a superoxide radical flux. Acute wound fluid contained higher protein carbonyl content than chronic wound fluid, particularly evident following sodium dodecyl sulfate-polyacrylamide gel electrophoresis/Western blot analysis under nonreducing and reducing conditions (p < 0.001 and p < 0.02, respectively), related to significantly higher protein levels (p = 0.0005) in acute wound fluid. Human serum albumin ( approximately 66 kDa) was identified as the most prominent protein oxidized in both acute and chronic wound fluid, which may contribute to the reduced albumin and total protein levels in chronic wound fluid. No significant difference (p > 0.1) in malondialdehyde levels or total antioxidant capacities were determined between acute and chronic wound fluids, although chronic wound fluid exhibited significantly higher total antioxidant capacities (p < 0.005), accounting for variations in wound fluid protein content. These findings suggest an adaptation in the antioxidant profiles of chronic wound fluid to counteract the loss of consumed antioxidants in the chronic wound environment. This study highlights the roles of ROS/antioxidants in skin wound healing, their possible involvement in chronic wounds and the potential value of ROS-induced biomarkers in wound healing prognosis.

The effect of polylactide membranes on the levels of reactive oxygen species in periodontal flaps during wound healing

It is consented that reactive oxygen species (ROS) are deleterious to wound healing process due to the harmful effects on cells and tissues. Absorbable synthetic biomaterials are considered to be degraded via ROS. Free-radical-scavenging enzymes (FRSE) are a cytoprotective enzymal group that has an essential role in the reduction, de-activation and removal of ROS as well as regulating wound healing process. In the present study, synthetic and absorbable polylactide (PLA) barrier membranes were evaluated by means of ROS activity levels during degradation in the healing periodontal flaps measuring the activity of FRSE superoxide dismutase (SOD) and catalase (CAT). Gingival biopsies taken from 10 patients allowing both guided tissue regeneration (test) and conventional flap surgery (control) before and 1 month after the operations were processed and the supernatants were studied by Mc Cord and Fridovich, Flohe and Otting, and Luck methods to measure total SOD and CAT levels respectively. A significantly increased enzyme activity of SOD and CAT was observed in both groups (p<0.05). SOD activity change was 62.92% in the test and 3.97% in the control group, and, CAT activity change was 48.04% in the test and 11.58% in the control group. Our results suggest that ROS, particularly superoxide anions, may contribute to the degradation phase of PLA membranes and this may affect the wound healing of periodontium at least for one-month period.

Dietary zinc alters early inflammatory responses during cutaneous wound healing in weanling CD-1 mice

Zinc deficiency is a well-known health problem associated with delayed wound healing, yet the precise mechanisms that underlie the delay remain unknown. We hypothesized that zinc deficiency delays wound healing as a result of decreased nuclear factor (NF)kappaB activation, reduced expression of proinflammatory cytokines [interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha], and a decrease in neutrophil infiltration during the early stage of cutaneous wound healing. We used a cutaneous, full-thickness excisional wound model in CD-1 mice to examine the rate of wound closure as well as mRNA levels of inhibitory (I)kappaBalpha, IL-1beta, and TNF-alpha and infiltration of neutrophils at the wound site of mice fed a diet containing <1 (deficient), 50 (control), 500, or 1000 microg zinc/g diet. Zinc deficiency reduced the rate of wound closure and mRNA levels of IL-1beta and TNF-alpha and attenuated infiltration of neutrophils at the wound site compared with controls. Interestingly, zinc supplementation at 1000 microg/g delayed the rate of wound closure and decreased mRNA levels of TNF-alpha and infiltration of neutrophils compared with mice fed the control diet. These findings demonstrate that zinc deficiency and high-dose zinc supplementation delay wound healing as a result of altered inflammatory responses and suggest that adequate zinc supplementation may have beneficial effects on the inflammatory responses to enhance cutaneous wound healing.

Extracellular matrix metabolites as potential biomarkers of disease activity in wound fluid: lessons learned from other inflammatory diseases?

The new era of pharmacogenetics has identified a potential for individuals to receive customized treatments for a variety of disease states. For such individualized treatments to fulfil their potential, it will be essential for clinicians to be able to monitor disease activity, ideally in a rapid, noninvasive fashion. The accessibility of the skin offers much potential to develop noninvasive tests of metabolic and disease activity for clinical use. Impaired human wound healing in the skin is a chronic inflammatory disorder in which the development of such tests has considerable potential, aiding clinical decision making and monitoring responses to treatment. This review article discusses how studies in other human diseases have highlighted potential biochemical markers (biomarkers) of disease activity in secreted biofluids, as aids to determining disease and metabolic activity within tissues. Using, as examples, lessons learned in the study of disease activity and prognosis of other chronic inflammatory conditions, such as osteoarthritis and periodontal disease, this review highlights the potential of dermal extracellular matrix (ECM) components (collagens, proteoglycans, hyaluronan and glycoproteins) for such uses. The limitations of currently utilized techniques and the concept that analysis of ECM components in wound fluid may represent useful biomarkers of disease activity are also discussed.