Polarisation of human macrophages towards an M1 subtype triggered by an atypical Brazilian strain of Toxoplasma gondii results in a reduction in parasite burden.

Toxoplasma gondii Nicolle et Manceaux, 1909, the etiologic agent of toxoplasmosis, was considered a clonal population with three distinct genetic lineages (I, II and III); however, sequence analysis of different strains has revealed distinct atypical genotypes. Macrophages are essential for immunity against toxoplasmosis and differential cell regulation may affect the course of the disease. In this context, our study aims to investigate the infection by TgChBrUD2, a highly virulent atypical Brazilian strain of T. gondii, on the activation and polarisation of human macrophages. Human macrophage-like cells obtained from THP-1 cells were infected with TgChBrUD2, RH or ME49 strains of T. gondii to evaluate the impact of parasite infection on macrophage polarisation. Our results indicate that the TgChBrUD2 and ME49 strains of T. gondii induced a classic activation of human macrophages, which was confirmed by the high rate of spindle-shaped macrophages, low amount of urea and increase in the levels of nitrite, as well as the down-regulation of M2-markers. In contrast, RH strain promoted an alternative activation of macrophages. The polarisation of human macrophages towards an M1 subtype mediated by TgChBrUD2 and ME49 strains resulted in a low parasite burden, with high levels of IL-6 and MIF. Finally, the M2 subtype triggered by the RH strain culminated in a lower intracellular proliferation index. We concluded that the atypical (TgChBrUD2) and clonal (ME49) strains are able to elicit an M1 subtype, which results in parasitism control, partially explained by the high levels of IL-6 and MIF produced during the infection by these genotypes. In contrast, the clonal (RH) strain promoted a macrophage polarisation towards an M2 subtype, marked by a high parasite burden, with a weak modulation of pro-inflammatory cytokines. Thus, atypical strains can present different mechanisms of pathogenicity and transmissibility compared to clonal strains, as well as they can use distinct strategies to evade the host's immune response and ensure their survival.

Human rhinovirus infection causes different DNA methylation changes in nasal epithelial cells from healthy and asthmatic subjects.

BACKGROUND: Mechanisms underlying the development of virus-induced asthma exacerbations remain unclear. To investigate if epigenetic mechanisms could be involved in virus-induced asthma exacerbations, we undertook DNA methylation profiling in asthmatic and healthy nasal epithelial cells (NECs) during Human Rhinovirus (HRV) infection in vitro. METHODS: Global and loci-specific methylation profiles were determined via Alu element and Infinium Human Methylation 450 K microarray, respectively. Principal components analysis identified the genomic loci influenced the most by disease-status and infection. Real-time PCR and pyrosequencing were used to confirm gene expression and DNA methylation, respectively. RESULTS: HRV infection significantly increased global DNA methylation in cells from asthmatic subjects only (43.6% to 44.1%, p = 0.04). Microarray analysis revealed 389 differentially methylated loci either based on disease status, or caused by virus infection. There were disease-associated DNA methylation patterns that were not affected by HRV infection as well as HRV-induced DNA methylation changes that were unique to each group. A common methylation locus stood out in response to HRV infection in both groups, where the small nucleolar RNA, H/ACA box 12 (SNORA12) is located. Further analysis indicated that a relationship existed between SNORA12 DNA methylation and gene expression in response to HRV infection. CONCLUSIONS: We describe for the first time that Human rhinovirus infection causes DNA methylation changes in airway epithelial cells that differ between asthmatic and healthy subjects. These epigenetic differences may possibly explain the mechanism by which respiratory viruses cause asthma exacerbations.

Asthmatics with exacerbation during acute respiratory illness exhibit unique transcriptional signatures within the nasal mucosa.

BACKGROUND: Acute respiratory illness is the leading cause of asthma exacerbations yet the mechanisms underlying this association remain unclear. To address the deficiencies in our understanding of the molecular events characterizing acute respiratory illness-induced asthma exacerbations, we undertook a transcriptional profiling study of the nasal mucosa over the course of acute respiratory illness amongst individuals with a history of asthma, allergic rhinitis and no underlying respiratory disease. METHODS: Transcriptional profiling experiments were performed using the Agilent Whole Human Genome 4X44K array platform. Time point-based microarray and principal component analyses were conducted to identify and distinguish acute respiratory illness-associated transcriptional profiles over the course of our study. Gene enrichment analysis was conducted to identify biological processes over-represented within each acute respiratory illness-associated profile, and gene expression was subsequently confirmed by quantitative polymerase chain reaction. RESULTS: We found that acute respiratory illness is characterized by dynamic, time-specific transcriptional profiles whose magnitudes of expression are influenced by underlying respiratory disease and the mucosal repair signature evoked during acute respiratory illness. Most strikingly, we report that people with asthma who experience acute respiratory illness-induced exacerbations are characterized by a reduced but prolonged inflammatory immune response, inadequate activation of mucosal repair, and the expression of a newly described exacerbation-specific transcriptional signature. CONCLUSION: Findings from our study represent a significant contribution towards clarifying the complex molecular interactions that typify acute respiratory illness-induced asthma exacerbations.

Regulation and function of the IL-1 family cytokine IL-1F9 in human bronchial epithelial cells.

The IL-1 family of cytokines, which now includes 11 members, is well known to participate in inflammation. Although the most recently recognized IL-1 family cytokines (IL-1F5-11) have been shown to be expressed in airway epithelial cells, the regulation of their expression and function in the epithelium has not been extensively studied. We investigated the regulation of IL-1F5-11 in primary normal human bronchial epithelial cells. Messenger (m)RNAs for IL-1F6 and IL-1F9, but not IL-1F5, IL-1F8 or IL-1F10, were significantly up-regulated by TNF, IL-1ß, IL-17 and the Toll-like receptor (TLR)3 ligand double-stranded (ds)RNA. mRNAs for IL-1F7 and IL-1F11 (IL-33) were weakly up-regulated by some of the cytokines tested. Notably, mRNAs for IL-1F6 and IL-1F9 were synergistically enhanced by the combination of TNF/IL-17 or dsRNA/IL-17. IL-1F9 protein was detected in the supernatant following stimulation with dsRNA or a combination of dsRNA and IL-17. IL-1F6 protein was detected in the cell lysate but was not detected in the supernatant. We screened for the receptor for IL-1F9 and found that lung fibroblasts expressed this receptor. We found that IL-1F9 activated mitogen-activated protein kinases and the transcription factor NF-κB in primary normal human lung fibroblasts. IL-1F9 also stimulated the expression of the neutrophil chemokines IL-8 and CXCL3 and the Th17 chemokine CCL20 in lung fibroblasts. These results suggest that epithelial activation by TLR3 (e.g., by respiratory viral infection) and exposure to cytokines from Th17 cells (IL-17) and inflammatory cells (TNF) may amplify neutrophilic inflammation in the airway via induction of IL-1F9 and activation of fibroblasts.

Viral diversity in asthma.

Asthma exacerbations are precipitated primarily by respiratory virus infection and frequently require immediate medical intervention. Studies of childhood and adult asthma have implicated a wide variety of respiratory viruses in exacerbations. By focusing on both RNA and DNA respiratory viruses and some newly identified viruses, this review illustrates the diversity and highlights some of the uncertainties that exist in our understanding of virus-related asthma exacerbations.

Elevated CO2 selectively inhibits interleukin-6 and tumor necrosis factor expression and decreases phagocytosis in the macrophage.

Elevated blood and tissue CO(2), or hypercapnia, is common in severe lung disease. Patients with hypercapnia often develop lung infections and have an increased risk of death following pneumonia. To explore whether hypercapnia interferes with host defense, we studied the effects of elevated P(CO2) on macrophage innate immune responses. In differentiated human THP-1 macrophages and human and mouse alveolar macrophages stimulated with lipopolysaccharide (LPS) and other Toll-like receptor ligands, hypercapnia inhibited expression of tumor necrosis factor and interleukin (IL)-6, nuclear factor (NF)-kappaB-dependent cytokines critical for antimicrobial host defense. Inhibition of IL-6 expression by hypercapnia was concentration dependent, rapid, reversible, and independent of extracellular and intracellular acidosis. In contrast, hypercapnia did not down-regulate IL-10 or interferon-beta, which do not require NF-kappaB. Notably, hypercapnia did not affect LPS-induced degradation of IkappaB alpha, nuclear translocation of RelA/p65, or activation of mitogen-activated protein kinases, but it did block IL-6 promoter-driven luciferase activity in mouse RAW 264.7 macrophages. Elevated P(CO2) also decreased phagocytosis of opsonized polystyrene beads and heat-killed bacteria in THP-1 and human alveolar macrophages. By interfering with essential innate immune functions in the macrophage, hypercapnia may cause a previously unrecognized defect in resistance to pulmonary infection in patients with advanced lung disease.

In vitro susceptibility to rhinovirus infection is greater for bronchial than for nasal airway epithelial cells in human subjects.

BACKGROUND: Human rhinoviruses (HRVs) characteristically cause upper respiratory tract infection, but they also infect the lower airways, causing acute bronchitis and exacerbating asthma. OBJECTIVE: Our purpose was to study ex vivo the differences in the response to HRV infection of nasal and bronchial epithelial cultures from the same healthy and asthmatic individuals using conditions favoring development of fully differentiated, pseudostratified mucociliary epithelium. METHODS: Cells from the inferior turbinates and bronchial tree of 5 healthy and 6 asthmatic individuals were cultured at an air-liquid interface. Cultures were infected with HRV-16, and after 48 hours, the degree of infection was measured. RESULTS: Baseline median transepithelial resistance was lower in human bronchial epithelial (HBE) cell cultures than in human nasal epithelial (HNE) cell cultures (195 Omega.cm2 [95% CI, 164-252] vs 366 Omega.cm2 [95% CI, 234-408], respectively; P < .01). Virus replicated more easily in HBE cells than in HNE cells based on virus shedding in apical wash (log tissue culture infective dose of 50%/0.1 mL = 2.0 [95% CI, 1.0-2.5] vs 0.5 [95% CI, 0.5-1.5], P < .01) and on a 20- to 30-fold greater viral load and number of infected cells in HBE cell cultures than in HNE cell cultures. The increases in expression of RANTES and double-stranded RNA-dependent protein kinase were greater in HBE cell cultures than in HNE cell cultures, as were the concentrations of IL-8, IL-1alpha, RANTES, and IP-10 in basolateral medium. However, no significant differences between asthmatic and healthy subjects (including IFN-beta1 expression) were found. CONCLUSIONS: Differentiated nasal epithelial cells might have mechanisms of increased resistance to rhinovirus infection compared with bronchial epithelial cells. We could not confirm previous reports of increased susceptibility to HRV infection in epithelial cells from asthmatic subjects.

Epithelium, inflammation, and immunity in the upper airways of humans: studies in chronic rhinosinusitis.

The purpose of this review is to discuss recent findings made during studies of the upper airways and sinuses of people with chronic rhinosinusitis (CRS) in the context of the literature. CRS is a chronic inflammatory disorder affecting nearly 30 million Americans and is generally resistant to therapy with antibiotics and glucocorticoids (Meltzer EO and coworkers, J Allergy Clin Immunol 2004;114:155-212). We have formed a collaboration that consists of otolaryngologists, allergists, and basic scientists to address the underlying immunologic and inflammatory processes that are occurring in, and possibly responsible for, this disease. The main emphasis of our work has been to focus on the roles that epithelium, in the sinuses and upper airways, plays as both a mediator and regulator of immune and inflammatory responses. It is not our intention here to provide a comprehensive review of the literature in this area, but we will try to put our work in the context of the findings of others (Kato A and Schleimer RP, Curr Opin Immunol 2007;19:711-720; Schleimer RP and coworkers, J Allergy Clin Immunol 2007;120:1279-1284). In particular, we discuss the evidence that epithelial cell responses are altered in CRS, including those relevant to regulation of dendritic cells, T cells, B cells, and barrier function.

12/15-Lipoxygenase deficiency protects mice from allergic airways inflammation and increases secretory IgA levels.

BACKGROUND: Induction of 15-lipoxygenase-1 (15-LO-1) has been observed in the airways of subjects with asthma, although its physiologic role in the airways has remained largely undefined. OBJECTIVES: We sought to test the hypothesis that the mouse 15-LO-1 ortholog 12/15-LO contributes to the development of allergic airways inflammation. METHODS: Two models were used to evaluate wild-type and 12/15-LO-deficient mice. The systemic model involved intraperitoneal injections of allergen, and the mucosal model involved allergen exposures occurring exclusively in the airways. The systemic and mucosal-specific contributions of 12/15-LO to allergic sensitization and airways inflammation were determined by comparing the results obtained in the 2 models. RESULTS: In the mucosal model 12/15-LO knockout mice were protected from the development of allergic sensitization and airways inflammation, as evidenced by circulating levels of allergen-specific IgE, IgG1, and IgG2a; the profile of inflammatory cells in bronchoalveolar lavage fluid; and the expression of cytokines and mediators in lung tissue. In the systemic model 12/15-LO knockout mice were not protected. This suggested the presence of a lung-restricted protective role for 12/15-LO deficiency that was potentially accounted for by increased activation of mucosal B cells and increased production of the known mucosal-specific protective mediator secretory IgA. CONCLUSIONS: Induction of 15-LO-1 in asthma might contribute to allergic sensitization and airways inflammation, potentially by causing suppression of secretory IgA.

The epithelial anion transporter pendrin is induced by allergy and rhinovirus infection, regulates airway surface liquid, and increases airway reactivity and inflammation in an asthma model.

Asthma exacerbations can be triggered by viral infections or allergens. The Th2 cytokines IL-13 and IL-4 are produced during allergic responses and cause increases in airway epithelial cell mucus and electrolyte and water secretion into the airway surface liquid (ASL). Since ASL dehydration can cause airway inflammation and obstruction, ion transporters could play a role in pathogenesis of asthma exacerbations. We previously reported that expression of the epithelial cell anion transporter pendrin is markedly increased in response to IL-13. Herein we show that pendrin plays a role in allergic airway disease and in regulation of ASL thickness. Pendrin-deficient mice had less allergen-induced airway hyperreactivity and inflammation than did control mice, although other aspects of the Th2 response were preserved. In cultures of IL-13-stimulated mouse tracheal epithelial cells, pendrin deficiency caused an increase in ASL thickness, suggesting that reductions in allergen-induced hyperreactivity and inflammation in pendrin-deficient mice result from improved ASL hydration. To determine whether pendrin might also play a role in virus-induced exacerbations of asthma, we measured pendrin mRNA expression in human subjects with naturally occurring common colds caused by rhinovirus and found a 4.9-fold increase in mean expression during colds. Studies of cultured human bronchial epithelial cells indicated that this increase could be explained by the combined effects of rhinovirus and IFN-gamma, a Th1 cytokine induced during virus infection. We conclude that pendrin regulates ASL thickness and may be an important contributor to asthma exacerbations induced by viral infections or allergens.

Candida albicans modulates host defense by biosynthesizing the pro-resolving mediator resolvin E1.

Candida albicans is an opportunistic fungal pathogen of humans that resides commensally on epithelial surfaces, but can cause inflammation when pathogenic. Resolvins are a class of anti-inflammatory lipids derived from omega-3 polyunsaturated fatty acids (PUFA) that attenuate neutrophil migration during the resolution phase of inflammation. In this report we demonstrate that C. albicans biosynthesizes resolvins that are chemically identical to those produced by human cells. In contrast to the trans-cellular biosynthesis of human Resolvin E1 (RvE1), RvE1 biosynthesis in C. albicans occurs in the absence of other cellular partners. C. albicans biosynthesis of RvE1 is sensitive to lipoxygenase and cytochrome P450 monoxygenase inhibitors. We show that 10nM RvE1 reduces neutrophil chemotaxis in response to IL-8; 1nM RvE1 enhanced phagocytosis of Candida by human neutrophils, as well as intracellular ROS generation and killing, while having no direct affect on neutrophil motility. In a mouse model of systemic candidiasis, RvE1 stimulated clearance of the fungus from circulating blood. These results reveal an inter-species chemical signaling system that modulates host immune functions and may play a role in balancing host carriage of commensal and pathogenic C. albicans.

TLR3- and Th2 cytokine-dependent production of thymic stromal lymphopoietin in human airway epithelial cells.

Thymic stromal lymphopoietin (TSLP) is elevated in asthma and triggers dendritic cell-mediated activation of Th2 inflammatory responses. Although TSLP has been shown to be produced mainly by airway epithelial cells, the regulation of epithelial TSLP expression has not been extensively studied. We investigated the expression of TSLP in cytokine- or TLR ligand-treated normal human bronchial epithelial cells (NHBE). The mRNA for TSLP was significantly up-regulated by stimulation with IL-4 (5.5-fold) and IL-13 (5.3-fold), weakly up-regulated by TNF-alpha, TGF-beta, and IFN-beta, and not affected by IFN-gamma in NHBE. TSLP mRNA was only significantly up-regulated by the TLR3 ligand (dsRNA) among the TLR ligands tested (66.8-fold). TSLP was also induced by in vitro infection with rhinovirus. TSLP protein was detected after stimulation with dsRNA (120 +/- 23 pg/ml). The combination of TNF-alpha and IL-4 produced detectable levels of TSLP protein (40 +/- 13 pg/ml). In addition, TSLP was synergistically enhanced by a combination of IL-4 and dsRNA (mRNA; 207-fold, protein; 325 +/- 75 pg/ml). The induction of TSLP by dsRNA was dependent upon NF-kappaB and IFN regulatory factor 3 (IRF-3) signaling via TLR3 as indicated by a study with small interfering RNA. The potent topical glucocorticoid fluticasone propionate significantly suppressed dsRNA-dependent TSLP production in NHBE. These results suggest that the expression of TSLP is induced in airway epithelial cells by stimulation with the TLR3 ligand and Th2 cytokines and that this response is suppressed by glucocorticoid treatment. This implies that respiratory viral infection and the recruitment of Th2 cytokine producing cells may amplify Th2 inflammation via the induction of TSLP in the asthmatic airway.

Protective effect of lectin from Synadenium carinatum on Leishmania amazonensis infection in BALB/c mice.

The protective effect of the Synadenium carinatum latex lectin (ScLL), and the possibility of using it as an adjuvant in murine model of vaccination against American cutaneous leishmaniasis, were evaluated. BALB/c mice were immunized with the lectin ScLL (10, 50, 100 microgram/animal) separately or in association with the soluble Leishmania amazonensis antigen (SLA). After a challenge infection with 10(6) promastigotes, the injury progression was monitored weekly by measuring the footpad swelling for 10 weeks. ScLL appeared to be capable of conferring partial protection to the animals, being most evident when ScLL was used in concentrations of 50 and 100 microgram/animal. Also the parasite load in the interior of macrophages showed significant reduction (61.7%) when compared to the control group. With regard to the cellular response, ScLL 50 and 100 microgram/animal stimulated the delayed-type hypersensitivity (DTH) reaction significantly (P < 0.05) higher than SLA or SLA plus ScLL 10 weeks after the challenge infection. The detection of high levels of IgG2a and the expression of mRNA cytokines, such as IFN-gamma, IL-12, and TNF-alpha (Th1 profiles), corroborated the protective role of this lectin against cutaneous leishmaniasis. This is the first report of the ScLL effect on leishmaniasis and shows a promising role for ScLL to be explored in other experimental models for treatment of leishmaniasis.

Levels of immunoglobulin A1 and messenger RNA for interferon gamma and tumor necrosis factor alpha in total saliva from patients with diabetes mellitus type 2 with chronic periodontal disease.

BACKGROUND: Diabetes mellitus and periodontal disease have high incidence in the general population and are associated with various degrees of dysfunction in the immune system. It has been shown that diabetic patients with severe periodontal disease have more complications of diabetes and less effective metabolic control compared with diabetic patients with healthy gingiva. Patients with diabetes and severe periodontal disease present higher levels of serous immunoglobulin A (IgA). Elevation of the IgA1 isotype is thought to contribute to this phenomenon. Another important event in the diabetes-periodontitis association is the disturbance in local and systemic production of inflammatory cytokines. OBJECTIVE: In this study we tested the hypothesis that type 2 diabetic patients with chronic moderate periodontal disease have differences in salivary IgA1 titers and cytokine expression when compared with the chronic severe periodontal disease cases. METHODS: We utilized a jacalin-IgA capture assay to determine the IgA1 titers in total saliva and reverse transcriptase-polymerase chain reaction to detect mRNA for interferon gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) in total saliva samples of 13 patients with chronic moderate periodontal disease and 10 with chronic severe periodontal disease. RESULTS AND CONCLUSIONS: We observed a predominance of IgA1 titers of 64 (45.5%) in saliva samples from chronic severe periodontal disease patients and titers averaging 512 (30.8%) in chronic moderate periodontal disease patients. We detected mRNA for IFN-gamma in six out of 10 chronic severe periodontal disease subjects and in two out of 13 chronic moderate periodontal disease patients. TNF-alpha expression was similar in both groups. Our data suggest that higher levels of IgA1 may exert partial protection of the periodontal tissue in chronic moderate periodontal disease diabetic patients when compared to severe periodontal disease. Despite the small number of patients, IFN-gamma expression had a trend association with severity of periodontitis and TNF-alpha gene expression did not correlate with severity of periodontal disease.

A distinctive alveolar macrophage activation state induced by cigarette smoking.

RATIONALE: Macrophages are believed to play a central role in emphysema based largely on data from mouse models. However, the relevance of these models to smoking-related lung disease in humans is uncertain. OBJECTIVES: We sought to comprehensively characterize the effects of smoking on gene expression in human alveolar macrophages and to compare these with effects seen in transgenic mouse models of emphysema. METHODS: We used DNA microarrays with genomewide coverage to analyze alveolar macrophages from 15 smokers, 15 nonsmokers, and 15 subjects with asthma (disease control). Selected gene expression changes were validated by polymerase chain reaction and ELISA. Expression changes were compared with those identified by microarray analysis of interleukin-13-overexpressing and integrin-beta6-deficient mice, which both develop emphysema. MEASUREMENTS AND MAIN RESULTS: All 15 smokers shared a common pattern of macrophage gene expression that distinguished them from nonsmokers, a finding not observed in subjects with asthma. We identified 110 genes as differentially expressed in smokers despite using conservative statistical methods. Matrix metalloproteinase 12, a proteinase that plays a critical role in mouse models, was the third most highly induced gene in smokers (ninefold, p < 0.0001). However, most changes in smokers were not reflected in mouse models. One such finding was increased osteopontin expression in smokers (fourfold, p = 0.006), which was confirmed at the protein level and correlated with the degree of airway obstruction. CONCLUSIONS: Smoking induces a remarkably consistent and distinctive pattern of alveolar macrophage activation. These studies identify aspects of mouse models that are directly relevant to human smokers and also reveal novel potential mediators of smoking-related diseases.

[Immunoglobulin isotype and IgG subclass profiles in American tegumentary leishmaniasis]. / Perfil de isotipos de imunoglobulinas e subclasses de IgG na leishmaniose tegumentar americana.

The present work investigated the serum antibody profiles in 37 patients with American tegumentary leishmaniasis, who were attended at Hospital de Clinicas - Universidade Federal de Uberlandia, MG, Brazil. The immunoglobulin class and IgG subclass profiles were analyzed by indirect ELISA using Leishmania (Leishmania) amazonensis soluble antigen. The antibody avidity was determined by 6 M urea treatment after incubation with immunoenzymatic conjugate. It was observed that 97% of the serum samples presented anti-Leishmania antibodies for IgE class, 94.6% IgG, 57.5% IgA and 21.5% IgM class. For IgG subclasses the profiles were in the following order of frequency: IgG1>IgG3>IgG2>IgG4. High avidity of anti-Leishmania IgE antibodies was found in 44.4% of the samples. On the other hand, moderate avidity of specific IgG and IgA was observed in 62.8% and 47.8% of samples, respectively. These results indicate a very complex antibody response profile against American tegumentary leishmaniasis.

Influence of topical administration of n-3 and n-6 essential and n-9 nonessential fatty acids on the healing of cutaneous wounds.

Injury triggers a series of physiological events at the wound site. These include an inflammatory response that is established shortly after the injury, which is then followed by an intense formation of tissue over a period of days. Poly- and monounsaturated fatty acids exert major functions on the inflammatory responses, either in the form of phospholipids anchored in the cell membrane or as soluble lipoic mediators. We present evidence that linolenic (n-3), linoleic (n-6), and oleic (n-9) fatty acids can modulate the closure of surgically induced skin wounds. We found that n-9 fatty acids induced faster wound closure when compared to n-3, n-6, and control. In addition, n-9 fatty acids strongly inhibited the production of nitric oxide at the wound site. A mild improvement on wound closure was observed in the n-6 fatty acid-treated animals concurrent with a peak in nitric oxide production at 48 hours postsurgery. N-3 fatty acid treatment significantly delayed wound closure. Furthermore, we showed that n-3 fatty acid induced a peak in nitric oxide at 3 hours postsurgery and an intense deposition of extracellular matrix after 5 days of treatment. Thus, our results suggest a relevant role and potential therapeutic implication for fatty acids on skin wound healing.