Local Sites Of Inflammation Research Articles

Role of C-Reactive Protein at Sites of Inflammation and Infection.

C-reactive protein (CRP) is an acute inflammatory protein that increases up to 1,000-fold at sites of infection or inflammation. CRP is produced as a homopentameric protein, termed native CRP (nCRP), which can irreversibly dissociate at sites of inflammation and infection into five separate monomers, termed monomeric CRP (mCRP). CRP is synthesized primarily in liver hepatocytes but also by smooth muscle cells, macrophages, endothelial cells, lymphocytes, and adipocytes. Evidence suggests that estrogen in the form of hormone replacement therapy influences CRP levels in the elderly. Having been traditionally utilized as a marker of infection and cardiovascular events, there is now growing evidence that CRP plays important roles in inflammatory processes and host responses to infection including the complement pathway, apoptosis, phagocytosis, nitric oxide (NO) release, and the production of cytokines, particularly interleukin-6 and tumor necrosis factor-α. Unlike more recent publications, the findings of early work on CRP can seem somewhat unclear and at times conflicting since it was often not specified which particular CRP isoform was measured or utilized in experiments and whether responses attributed to nCRP were in fact possibly due to dissociation into mCRP or lipopolysaccharide contamination. In addition, since antibodies for mCRP are not commercially available, few laboratories are able to conduct studies investigating the mCRP isoform. Despite these issues and the fact that most CRP research to date has focused on vascular disorders, there is mounting evidence that CRP isoforms have distinct biological properties, with nCRP often exhibiting more anti-inflammatory activities compared to mCRP. The nCRP isoform activates the classical complement pathway, induces phagocytosis, and promotes apoptosis. On the other hand, mCRP promotes the chemotaxis and recruitment of circulating leukocytes to areas of inflammation and can delay apoptosis. The nCRP and mCRP isoforms work in opposing directions to inhibit and induce NO production, respectively. In terms of pro-inflammatory cytokine production, mCRP increases interleukin-8 and monocyte chemoattractant protein-1 production, whereas nCRP has no detectable effect on their levels. Further studies are needed to expand on these emerging findings and to fully characterize the differential roles that each CRP isoform plays at sites of local inflammation and infection.

Autoinhibitory regulation of S100A8/S100A9 alarmin activity locally restricts sterile inflammation.

Autoimmune diseases, such as psoriasis and arthritis, show a patchy distribution of inflammation despite systemic dysregulation of adaptive immunity. Thus, additional tissue-derived signals, such as danger-associated molecular patterns (DAMPs), are indispensable for manifestation of local inflammation. S100A8/S100A9 complexes are the most abundant DAMPs in many autoimmune diseases. However, regulatory mechanisms locally restricting DAMP activities are barely understood. We now unravel for the first time, to our knowledge, a mechanism of autoinhibition in mice and humans restricting S100-DAMP activity to local sites of inflammation. Combining protease degradation, pull-down assays, mass spectrometry, and targeted mutations, we identified specific peptide sequences within the second calcium-binding EF-hands triggering TLR4/MD2-dependent inflammation. These binding sites are free when S100A8/S100A9 heterodimers are released at sites of inflammation. Subsequently, S100A8/S100A9 activities are locally restricted by calcium-induced (S100A8/S100A9)2 tetramer formation hiding the TLR4/MD2-binding site within the tetramer interphase, thus preventing undesirable systemic effects. Loss of this autoinhibitory mechanism in vivo results in TNF-α-driven fatal inflammation, as shown by lack of tetramer formation in crossing S100A9-/- mice with 2 independent TNF-α-transgene mouse strains. Since S100A8/S100A9 is the most abundant DAMP in many inflammatory diseases, specifically blocking the TLR4-binding site of active S100 dimers may represent a promising approach for local suppression of inflammatory diseases, avoiding systemic side effects.

Production of GFP and Luciferase-Expressing Reporter Macrophages for In Vivo Bioluminescence Imaging.

Macrophages have emerged as crucial regulators of tissue homeostasis, inflammation, and tissue regeneration. In vivo bioluminescence imaging could offer a powerful tool to study many poorly understood aspects of macrophage biology. Thus, we recently developed a straightforward method for the production of large numbers of green fluorescent protein (GFP) and firefly luciferase (fLUC)-expressing reporter macrophages for various in vivo bioluminescence imaging applications. Lentivirus vector containing the GFP/fLUC reporter gene is produced and mouse bone marrow macrophages are isolated following established protocols. Macrophages are then exposed to the lentivirus in the presence of 10μM cyclosporine for 24h. After a 24-h recovery period, the transduction is repeated. Three days after the second infection the cells are ready to be used in vivo. Following this cyclosporine-mediated double infection strategy up to 60% of the macrophages express GFP in flow cytometry. The macrophages maintain their ability to polarize to M1 and M2 phenotypes and, when injected to the systemic circulation of a mouse model, reporter cells are both easily detectable with BLI and migrate to a local site of inflammation. These GFP/fLUC-expressing reporter macrophages could prove to be useful tools to study the role of macrophages in health and disease.

Investigating Immune Gene Signatures in Peripheral Blood from Subjects with Allergic Rhinitis Undergoing Nasal Allergen Challenge.

Nasal allergen challenge (NAC) is a human model of allergic rhinitis (AR) that delivers standardized allergens locally to the nasal mucosa allowing clinical symptoms and biospecimens such as peripheral blood to be collected. Although many studies have focused on local inflammatory sites, peripheral blood, an important mediator and a component of the systemic immune response, has not been well studied in the setting of AR. We sought to investigate immune gene signatures in peripheral blood collected after NAC under the setting of AR. Clinical symptoms and peripheral blood samples from AR subjects were collected during NAC. Fuzzy c-means clustering method was used to identify immune gene expression patterns in blood over time points (before NAC and 1, 2, and 6 h after NAC). We identified and validated seven clusters of differentially expressed immune genes after NAC onset. Clusters 2, 3, and 4 were associated with neutrophil and lymphocyte frequencies and neutrophil/lymphocyte ratio after the allergen challenge. The patterns of the clusters and immune cell frequencies were associated with the clinical symptoms of the AR subjects and were significantly different from healthy nonallergic subjects who had also undergone NAC. Our approach identified dynamic signatures of immune gene expression in blood as a systemic immune response associated with clinical symptoms after NAC. The immune gene signatures may allow cross-sectional investigation of the pathophysiology of AR and may also be useful as a potential objective measurement for diagnosis and treatment of AR combined with the NAC model.

Interleukin-20 is triggered by TLR ligands and associates with disease activity in patients with rheumatoid arthritis

BackgroundInterleukin (IL)-20 is a pro-inflammatory cytokine that may be implicated in the pathogenesis of rheumatoid arthritis (RA). This study aimed to determine the association between IL-20 and disease activity in patients with RA. MethodsThe levels of serum and synovial fluid IL-20 were measured in patients with RA and OA. The disease activity was assessed based on the Disease Activity Score of 28 joints (DAS28). The expression of IL-20 in synovial tissue samples from patients with RA and OA were determined by immunohistochemistry. Immunofluorescence staining was used to co-localize IL-20 with selected cells. The secretion of IL-20 was analysed in human peripheral blood mononuclear cells (PBMCs) of patients with RA. ResultsSynovial fluid and synovial tissue IL-20 were significantly increased in patients with RA compared with patients with OA. The expression of IL-20 in RA synovial tissue was particularly associated with macrophages and neutrophil granulocytes, but also with synovial fibroblasts and lymphocytes. The IL-20 levels in synovial fluid correlated with DAS28 (r=0.434; p=0.015) and were significantly elevated in anti-CCP positive RA compared with anti-CCP negative RA (122.3±104.1pg/ml and 45.9±35.8pg/ml; p=0.008). IL-20 production from PBMCs was induced by Poly I:C and LPS but not with pro-inflammatory cytokines, such as TNF-α or IL-1. ConclusionOur data showed that IL-20 is independently associated with RA disease activity and may be triggered by TLR ligands at local sites of inflammation.

Local inflammation exacerbates cutaneous manifestations in a murine autoimmune pemphigus model

Local inflammation exacerbates cutaneous manifestations in a murine autoimmune pemphigus model

Cell penetrable-mouse forkhead box P3 suppresses type 1 T helper cell-mediated immunity in a murine model of delayed-type hypersensitivity

Forkhead box P3 (FOXP3), which is a transcription factor, has a primary role in the development and function of regulatory T cells, and thus contributes to homeostasis of the immune system. A previous study generated a cell-permeable fusion protein of mouse FOXP3 conjugated to a protein transduction domain (PTD-mFOXP3) that successfully blocked differentiation of type 17 T helper cells in vitro and alleviated experimental arthritis in mice. In the present study, the role of PTD-mFOXP3 in type 1 T helper (Th1) cell-mediated immunity was investigated and the possible mechanisms for its effects were explored. Under Th1 polarization conditions, cluster of differentiation 4+ T cells were treated with PTD-mFOXP3 and analyzed by flow cytometry in vitro, which revealed that PTD-mFOXP3 blocked Th1 differentiation in vitro. Mice models of delayed type hypersensitivity (DTH) reactions were generated by subcutaneous sensitization and challenge with ovalbumin (OVA) to the ears of mice. PTD-mFOXP3, which was administered via local subcutaneous injection, significantly reduced DTH-induced inflammation, including ear swelling (ear swelling, P<0.001; pinnae weight, P<0.05 or P<0.01 with 0.25 and 1.25 mg/kg PTD-mFOXP3, respectively), infiltration of T cells, and expression of interferon-γ at local inflammatory sites (mRNA level P<0.05) compared with the DTH group. The results of the present study demonstrated that PTD-mFOXP3 may attenuate DTH reactions by suppressing the infiltration and activity of Th1 cells.

Increased Levels of S100A8/A9 in Patients with Peritonsillar Abscess: A New Promising Diagnostic Marker to Differentiate between Peritonsillar Abscess and Peritonsillitis.

Peritonsillar abscess (PTA) is a very frequent reason for urgent outpatient consultation and otolaryngological hospital admission. Early, correct diagnosis and therapy of peritonsillar abscess are important to prevent possible life-threatening complications. Based on physical examinations, a reliable differentiation between peritonsillar cellulitis and peritonsillar abscess is restricted. A heterodimeric complex called calprotectin consists of the S100 proteins A8 and A9 (S100A8/A9) and is predominantly expressed not only in monocytes and neutrophils but also in epithelial cells. Due to its release by activated phagocytes at local sites of inflammation, we assumed S100A8/A9 to be a potential biomarker for peritonsillar abscess. We examined serum and saliva of patients with peritonsillitis, acute tonsillitis, peritonsillar abscess, and healthy controls and found significantly increased levels of S100A8/A9 in patients with PTA. Furthermore, we could identify halitosis, trismus, uvula edema, and unilateral swelling of the arched palate to be characteristic symptoms for PTA. Using a combination of these characteristic symptoms and S100A8/A9 levels, we developed a PTA score as an objective and appropriate tool to differentiate between peritonsillitis and peritonsillar abscess with a sensitivity of 92% and specificity of 93%.

Complement component 6 deficiency increases susceptibility to dextran sulfate sodium-induced murine colitis

As a potent effector of innate immunity, the complement system has been shown to be involved in the pathogenesis of inflammatory bowel disease (IBD). However, the role of the membrane attack complex (MAC) in the development of IBD is still largely unknown. Here, we used C6-deficient mice in which MAC formation was blocked due to the absence of C6 to develop an acute colitis model by the administration of dextran sulfate sodium (DSS). The results showed that DSS-induced colitis was aggravated in C6-deficient mice compared with wild-type (WT) mice, as represented by the markedly greater weight loss, higher disease activity index (DAI), shortened colon length, more severe histological injury with increased epithelial ulcerations, and massively increased infiltration of leukocytes accompanied by much higher myeloperoxidase (MPO) levels in local inflammatory colonic sites. In addition, the DSS-induced colitis in C6-deficient mice could be significantly ameliorated by the exogenous C6 from WT sera. Furthermore, the significantly enhanced production of pro-inflammatory mediators, including IL-1β, IL-6, CXCL-1, CCL-3, TGF-β1 and IL-17F, was also observed in C6-deficient mice. Unexpectedly, the aggravated colitis in C6-deficient mice may be not due to the increase of lipopolysaccharide (LPS) levels in serum. Overall, we demonstrated that MAC exerts a protective role in acute colitis, strongly highlighting the host defense function of the complement system.

Thy1+IL-7+ lymphatic endothelial cells in iBALT provide a survival niche for memory T-helper cells in allergic airway inflammation

Memory CD4(+) T helper (Th) cells are central to long-term protection against pathogens, but they can also be pathogenic and drive chronic inflammatory disorders. How these pathogenic memory Th cells are maintained, particularly at sites of local inflammation, remains unclear. We found that ectopic lymphoid-like structures called inducible bronchus-associated lymphoid tissue (iBALT) are formed during chronic allergic inflammation in the lung, and that memory-type pathogenic Th2 (Tpath2) cells capable of driving allergic inflammation are maintained within the iBALT structures. The maintenance of memory Th2 cells within iBALT is supported by Thy1(+)IL-7-producing lymphatic endothelial cells (LECs). The Thy1(+)IL-7-producing LECs express IL-33 and T-cell-attracting chemokines CCL21 and CCL19. Moreover, ectopic lymphoid structures consisting of memory CD4(+) T cells and IL-7(+)IL-33(+) LECs were found in nasal polyps of patients with eosinophilic chronic rhinosinusitis. Thus, Thy1(+)IL-7-producing LECs control chronic allergic airway inflammation by providing a survival niche for memory-type Tpath2 cells.

Abstract A33: Preparation of local anti-wart and anti-inflammatory rub of polyglycidol based saturated lipid (DDP-PG) with HPMC containing curcumin

Abstract Curcumin is absorbed poorly and has a limited bioavailability to work promptly as an anti-cancer drug or as an anti-inflammatory agent. If curcumin could be delivered directly into the cell, it might be a potential therapeutic against the inflammation and thereby cancer signaling cascades. In order to reach this goal here a topical medicament (rub) containing curcumin has been developed as an alternative therapeutic especially for skin inflammation and cancer thereby. We synthesized polyglycidol based block copolymers DDP-PG (MW 2700), which was incorporated into HPMC (7%) to prepare the rub containing curcumin. One more formulation containing monoolein rac glycerol (MO) with DDP-PG was incorporated. The diffusion of curcumin was evaluated in vitro using a biomembrane (fish swim bladder). The diffusion of curcumin form DDP-PG based formulation did not differ from that of MO, which is the indication of their suitability as biomaterials for the preparation of a transdermal penetrating vehicle. Subsequently, curcumin containing DDP-PG was evaluated directly for therapeutic purposes treating local apoptotic skin, inflammatory sites and benign tumor mass (wart). It showed skin cured very promisingly from apoptosis, which might be worst if not treated in time. It cleared the inflammation perfectly and reduced dramatically the size of the wart (a benign tumor) as well. Citation Format: Sharif Mohammad Shaheen, Pavel Bakardzhiev, Denitsa Momekova, Neli S. Koseva, Stanislav Rangelov. Preparation of local anti-wart and anti-inflammatory rub of polyglycidol based saturated lipid (DDP-PG) with HPMC containing curcumin. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy: A New Chapter; December 1-4, 2014; Orlando, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2015;3(10 Suppl):Abstract nr A33.

Detection of endogenous and food-derived collagen dipeptide prolylhydroxyproline (Pro-Hyp) in allergic contact dermatitis-affected mouse ear.

Generation of collagen dipeptides and deposition of orally administered prolylhydroxyproline (Pro-Hyp) in local inflammatory sites were examined in mice with hapten (2,4-dinitrofluorobenzene)-induced dermatitis in the ear. Pro-Hyp content in the hapten-treated ear was significantly higher in the chronic phase of contact dermatitis than the vehicle control. In contrast, hydroxyprolylglycine contents remained at lower levels in all cases compared to Pro-Hyp. Four hours after the ingestion of [(13)C5,(15)N]Pro and [(13)C5,(15)N]Pro-Hyp, labeled-Pro-Hyp and Pro, respectively, appeared only in the ear with dermatitis. Thus, Pro-Hyp is generated and degraded as part of the rapid synthesis and degradation of collagen in the ear with dermatitis. In addition to the endogenously generated Pro-Hyp, the orally administered Pro-Hyp was deposited in the ears.

In situ hematopoiesis: a regulator of TH2 cytokine-mediated immunity and inflammation at mucosal surfaces.

Hematopoiesis refers to the development of blood cells in the body through the differentiation of pluripotent stem cells. Although hematopoiesis is a multifocal process during embryonic development, under homeostatic conditions it occurs exclusively within the bone marrow. There, a limited number of hematopoietic stem cells differentiate into a rapidly proliferating population of lineage-restricted progenitors that serve to replenish circulating blood cells. However, emerging reports now suggest that under inflammatory conditions, alterations in hematopoiesis that occur outside of the bone marrow appear to constitute a conserved mechanism of innate immunity. Moreover, recent reports have identified previously unappreciated pathways that regulate the egress of hematopoietic progenitor cells from the bone marrow, alter their activation status, and skew their developmental potential. These studies suggest that progenitor cells contribute to inflammatory response by undergoing in situ hematopoiesis (ISH). In this review, we highlight the differences between homeostatic hematopoiesis, which occurs in the bone marrow, and ISH, which occurs at mucosal surfaces. Further, we highlight factors produced at local sites of inflammation that regulate hematopoietic progenitor cell responses and the development of TH2 cytokine-mediated inflammation. Finally, we discuss the therapeutic potential of targeting ISH in preventing the development of inflammation at mucosal sites.

Progranulin Is Associated with Disease Activity in Patients with Rheumatoid Arthritis.

Objective. Progranulin (PGRN) is implicated in the pathogenesis of rheumatoid arthritis (RA). The aim of this study was to assess the relationship between PGRN and disease activity in RA. Methods. PGRN levels were evaluated in patients with RA (n = 47) and OA (n = 42) and healthy controls (n = 41). Immunohistochemical analysis of PGRN in synovial tissues was performed. The association between PGRN and C-reactive protein (CRP), disease activity score (DAS28-CRP), and health assessment questionnaire (HAQ) was studied. Results. Circulating PGRN was elevated in patients with RA and OA compared to healthy controls (227.1 ± 100.2 and 221.5 ± 102.5 versus 128.1 ± 34.7 ng/mL; P < 0.001). Synovial fluid levels of PGRN were higher in patients with RA compared to OA (384.5 ± 275.3 versus 241.4 ± 165.2 ng/mL; P = 0.002). PGRN expression was significantly upregulated in the synovial tissue of RA patients particularly in the inflammatory infiltrates. Serum PGRN levels correlated with DAS28 (r = 0.327, P = 0.049) and HAQ score (r = 0.323, P = 0.032), while synovial fluid PGRN correlated only with HAQ (r = 0.310, P = 0.043) in patients with RA. PGRN levels were not associated with CRP or autoantibodies. Conclusions. This study demonstrates increased PGRN expression at local sites of inflammation and association between PGRN levels, disease activity, and functional impairment in patients with RA.

Development and evaluation of a non-peptidic ligand for the molecular imaging of inflammatory processes using S100A9 (MRP14) as a novel target.

The establishment of novel molecular imaging tools to monitor the local activity of inflammation remains an interdisciplinary challenge. Our target, the alarmin S100A9, one subunit of the heterodimer S100A8/S100A9 (calprotectin), is locally secreted in high concentrations from immigrated and activated phagocytes at local sites of inflammation. Calprotectin is already a well established serum biomarker for many inflammatory disorders. Here we show the development and first evaluation of the novel S100A9 specific molecular imaging probe for optical imaging of local inflammatory activity in vivo.

Neutrophils exhibit differential requirements for homing molecules in their lymphatic and blood trafficking into draining lymph nodes.

Although much is described about the molecules involved in neutrophil migration from circulation into tissues, less is known about the molecular mechanisms that regulate neutrophil entry into lymph nodes (LNs) draining a local inflammatory site. In this study, we investigated neutrophil migration toward LNs in a context of inflammation induced by immunization of BALB/c mice with OVA emulsified in CFA. We demonstrated that neutrophils can enter LNs of OVA/CFA-immunized mice not only via lymphatic vessels but also from blood, across high endothelial venules. By adoptive transfer experiments, we showed that this influx was dependent on an inflammatory-state condition and previous neutrophil stimulation with OVA/anti-OVA immune complexes. Importantly, we have demonstrated that, in the migratory pattern to LNs, neutrophils used L-selectin and P-selectin glycoprotein ligand-1, macrophage-1 Ag and LFA-1 integrins, and CXCR4 to get access across high endothelial venules, whereas macrophage-1 Ag, LFA-1, and CXCR4 were involved in their trafficking through afferent lymphatics. Strikingly, we found that stimulation with immune complexes significantly upregulated the expression of sphingosine-1-phosphate receptor 4 on neutrophils, and that treatment with the sphingosine-1-phosphate agonist FTY720 altered neutrophil LN-homing ability. These findings summarized in this article disclose the molecular pattern that controls neutrophil recruitment to LNs.

Immune suppression via glucocorticoid-stimulated monocytes: a novel mechanism to cope with inflammation.

Glucocorticoids (GCs) are used as first-line therapies for generalized suppression of inflammation (e.g., allergies or autoimmune diseases), but their long-term use is limited by severe side effects. Our previous work revealed that GCs induced a stable anti-inflammatory phenotype in monocytes, the GC-stimulated monocytes (GCsMs) that we exploited for targeted GC-mediated therapeutic effects. We demonstrate that GCsMs interact with T cells in suppressing proliferation, as well as cytokine release of CD8(+) and, especially, CD4(+) T cells in vitro, and that they support generation of Foxp3(+) cells. Therefore, we tested their immunosuppressive potential in CD4(+) T cell-induced colitis in vivo. We found that injection of GCsMs into mice with severe colitis abolished the inflammation and resulted in significant clinical improvement within a few days. T cells recovered from GCsM-treated mice exhibited reduced secretion of proinflammatory cytokines IFN-γ and IL-17. Furthermore, clusters of Foxp3(+) CD4(+) T cells were detectable at local sites of inflammation in the colon. Thus, GCsMs are able to modify T cell responses in vitro and in vivo, as well as to downregulate and clinically cure severe T cell-mediated colitis.

Local melatonin regulates inflammation resolution: a common factor in neurodegenerative, psychiatric and systemic inflammatory disorders.

In many psychiatric, neurodegenerative and systemic inflammatory disorders circadian melatonin is decreased whilst melatonin enzymes and melatonin receptors are genetic susceptibility factors. Treatment with melatonin is useful in a diverse range of medical conditions, including bipolar disorder, Alzheimer's disease, depression and fibromyalgia. Decreased melatonin effects are classically attributed to lost pineal production. However, melatonin, along with its immediate precursor N-acetylserotonin (NAS), is produced by many, if not all, mitochondrial containing cells, including immune cells and central glia. Here we review the data on local melatonin and NAS production and propose that astrocyte melatonin and NAS efflux is crucial to local central inflammation regulation at the glia-neuronal interface. Melatonin and NAS provide antioxidant and anti-inflammatory effects, as well as increasing mitochondrial oxidative phosphorylation and functioning. Consequently, their decreased production at sites of local inflammation is proposed to underlie melatonin's genetic association with a diverse range of medical conditions. Similarly the benefits of serotonin boosting medications, including antidepressants, across a wide range of conditions are partly mediated by increasing serotonin availability for astrocytic local NAS and melatonin production. Such a conceptualization incorporates a plethora of data across different disorders, especially the commonalities in oxidative and nitrosative stress, anti-oxidants, tryptophan catabolites and mitochondrial dysregulation evident in a diverse array of medical conditions. Glia melatonin and NAS regulation are important treatment targets in psychiatric disorders, neurodegenerative disorders and glioma.

Tumor necrosis factor-α promoter -308/238 polymorphism association with less severe disease in ankylosing spondylitis is unrelated to serum TNF-α and does not predict TNF inhibitor response.

Despite the clinical efficacy of tumor necrosis factor inhibitors (TNFi), the manner in which TNF-α contributes to disease in patients with ankylosing spondylitis (AS) remains unresolved. We investigated the relationship between TNF-α gene promoter region polymorphism, serum TNF-α levels, and clinical phenotype. We did a cross-sectional and longitudinal cohort study in TNFi-naive patients with AS (n = 335). Clinical data and biological samples were collected during a research visit with genotyping for TNF-α -238 A/G and -308 A/G performed by Taqman RT-PCR and TNF levels determined by sandwich ELISA. Longitudinal TNF levels were monitored in unselected patients (n = 61). TNF-α -308 GA/AA genotype was present in 14% and TNF-α -238 GA/AA genotype in 1% of patients. TNF-α -308 GA/AA genotype was associated with a reduced risk of uveitis and better spinal function, while TNF-α -238 GA/AA genotype was associated with later age of onset and lower erythrocyte sedimentation rate (ESR). Serum TNF-α level was lower in patients with AS (151 pg/ml) than in controls (263 pg/ml), because more patients with AS had undetectable serum TNF-α (66 vs 25%, p < 0.001). TNFi treatment did not influence serum TNF-α. There was no effect of TNF-α -308/-238 or HLA-B27 genotype on serum TNF-α or subsequent initiation of TNFi. TNF-α -238 or -308 GA/AA genotypes in patients with AS are associated with signs of less severe disease. Serum TNF-α is, however, undetectable in two-thirds of patients with AS and is not influenced by TNF-α promoter genotype or TNFi therapy. These data suggest a more significant role for TNF-α at local sites of inflammation in AS than through systemic effects.

High Concentration but Low Activity of Hepatocyte Growth Factor in Periodontitis

High levels of hepatocyte growth factor (HGF), a healing factor with regenerative and cytoprotective effects, are associated with inflammatory diseases, including periodontitis. HGF biologic activity requires binding to its receptors, the proto-oncogene c-Met and heparan sulfate proteoglycan (HSPG). This study investigates HGF expression and its relationship to subgingival microbiota in medically healthy individuals with and without periodontitis. Saliva, gingival crevicular fluid (GCF), and blood samples from 30 patients with severe periodontitis and 30 healthy controls were analyzed for HGF concentration using enzyme-linked immunosorbent assay and binding affinity for HSPG and c-Met using surface plasmon resonance. The regenerative effects of saliva from three patients and controls were analyzed in an in vitro model of cell injury. Subgingival plaques were analyzed for the presence of 18 bacterial species. Patients with periodontitis showed higher HGF concentrations in saliva, GCF, and serum (P <0.001); however, the binding affinities for HSPG and c-Met were reduced in GCF and saliva (P <0.002). In contrast to the controls, saliva from patients showed no significant regenerative effect over time on gingival epithelial cells. Compared with controls, patients had a higher prevalence of periodontally related bacteria. Higher circulatory HGF levels indicate a systemic effect of periodontitis. However, the HGF biologic activity at local inflammation sites was reduced, and this effect was associated with the amount of periodontal bacteria. Loss of function of healing factors may be an important mechanism in degenerative processes in periodontally susceptible individuals.