Adhesion pathway proteins and risk of atrial fibrillation in the Multi-Ethnic Study of Atherosclerosis.

BACKGROUND: The cellular adhesion pathway has been suggested as playing an important role in the pathogenesis of atrial fibrillation (AF). However, prior studies that have investigated the role of adhesion pathway proteins in risk of AF have been limited in the number of proteins that were studied and in the ethnic and racial diversity of the study population. Therefore we aimed to study the associations of fifteen adhesion pathway proteins with incident AF in a large, diverse population. METHODS: Multi-Ethnic Study of Atherosclerosis participants from four races/ethnicities (n = 2504) with protein levels measured were followed for incident AF (n = 253). HGF protein was measured on Exam 1 samples (N = 6669; AF n = 851). Cox proportional hazards regression was used to assess the association of AF with 15 adhesion pathway proteins. Bonferroni correction was applied to account for multiple comparisons. RESULTS: After adjusting for potential confounding variables (age, sex, race/ethnicity, height, body mass index, systolic blood pressure, antihypertension therapy, diabetes status, current smoker, current alcohol use, and total and HDL cholesterol), and accounting for multiple testing (P < 0.05/15 = 0.0033), circulating levels of the following proteins were positively associated with a higher risk of AF: MMP-2 (HR per standard deviation increment, 1.27; 95% CI 1.11‒1.45), TIMP-2 (HR 1.28; 95% CI 1.12‒1.46), VCAM-1 (HR 1.32; 95% CI 1.16‒1.50), and SLPI (HR 1.22; 95% CI 1.07‒1.38). The association between proteins and AF did not differ by race/ethnicity. CONCLUSIONS: Circulating levels of MMP-2, TIMP-2, VCAM-1, and SLPI were positively associated with an increased risk of incident AF in a diverse population. Our findings suggest that adhesion pathway proteins may be important risk predictors of AF.

SLPI - a Biomarker of Acute Kidney Injury after Open and Endovascular Thoracoabdominal Aortic Aneurysm (TAAA) Repair.

Acute kidney injury (AKI) is a relevant complication following thoracoabdominal aortic aneurysm repair (TAAA). Biomarkers, such as secretory leucocyte peptidase inhibitor (SLPI), may enable a more accurate diagnosis. In this study, we tested if SLPI measured in serum is an appropriate biomarker of AKI after TAAA repair. In a prospective observational single-center study including 33 patients (51.5% women, mean age 63.0 ± 16.2 years) undergoing open and endovascular aortic aneurysm repair in 2017, SLPI was measured peri-operatively (until 72 h after surgery). After surgery, the postoperative complications AKI, as defined according to the KDIGO diagnostic criteria, sepsis, death, MACE (major cardiovascular events) and, pneumonia were assessed. In a subgroup analysis, patients with preexisting kidney disease were excluded. Of 33 patients, 51.5% (n = 17) of patients developed AKI. Twelve hours after admission to the intensive care unit (ICU), SLPI serum levels were significantly increased in patients who developed AKI. Multivariable logistic regression revealed a significant association between SLPI 12 hours after admission to ICU and AKI (P = 0.0181, OR = 1.055, 95% CI = 1.009-1.103). The sensitivity of SLPI for AKI prediction was 76.47% (95% CI = 50.1-93.2) and the specificity was 87.5% (95% CI = 61.7-98.4) with an AUC = 0.838 (95% CI = 0.7-0.976) for an optimal cut-off 70.03 ng/ml 12 hours after surgery. In patients without pre-existing impaired renal function, an improved diagnostic quality of SLPI for AKI was observed (Sensitivities of 45.45-91.67%, Specificities of 77.7-100%, AUC = 0.716-0.932). There was no association between perioperative SLPI and the incidence of sepsis, death, MACE (major cardiovascular events), pneumonia. This study suggests that SLPI might be a post-operative biomarker of AKI after TAAA repair, with a superior diagnostic accuracy for patients without preexisting impaired renal function.

Plasma concentrations of secretory leukocyte protease inhibitor (SLPI) differ depending on etiology and severity in community-onset bloodstream infection.

The severity of bloodstream infections (BSI) depends on pathogen, source, and host factors. Secretory leukocyte protease inhibitor (SLPI) counteracts tissue damage, balances inflammation, and is increased in pneumonia and sepsis. We aimed to evaluate whether SLPI production differs depending on etiology, disease severity, and sex in BSI and to correlate SLPI with markers of inflammation and immunosuppression. Of the adult patients with BSI, 109 were included and sampled repeatedly, from hospital admission through day 28. Controls (blood donors) were sampled twice. SLPI in plasma was measured with enzyme-linked immunosorbent assay (ELISA) technique. Streptococcus pneumoniae and Staphylococcus aureus etiology were associated with higher SLPI than Escherichia coli on days 1-2 and 3. On day 1-2, subjects with sepsis had higher SLPI concentrations than those with non-septic BSI. Pneumonia was associated with higher SLPI than a non-pulmonary source of infection. SLPI co-varied with inflammatory markers. SLPI concentrations did not differ with regard to sex in the full cohort, but men with pneumonia had higher SLPI than women on day 1-2. S. pneumoniae and S. aureus BSI were associated with higher SLPI, when compared to E. coli. Severity and pneumonia, as well as male sex in the pneumonia sub-cohort, were factors independently associated with higher SLPI.

Donor biomarkers as predictors of organ use and recipient survival after neurologically deceased donor organ transplantation.

PURPOSE: We sought to build prediction models for organ transplantation and recipient survival using both biomarkers and clinical information. MATERIALS AND METHODS: We abstracted clinical variables from a previous randomized trial (n = 556) of donor management. In a subset of donors (n = 97), we measured two candidate biomarkers in plasma at enrollment and just prior to explantation. RESULTS: Secretory leukocyte protease inhibitor (SLPI) was significant for predicting liver transplantation (C-statistic 0.65 (0.53, 0.78)). SLPI also significantly improved the predictive performance of a clinical model for liver transplantation (integrated discrimination improvement (IDI): 0.090 (0.009, 0.210)). For other organs, clinical variables alone had strong predictive ability (C-statistic >0.80). Recipient 3-years survival was 80.0% (71.9%, 87.0%). Donor IL-6 was significantly associated with recipient 3-years survival (adjusted Hazard Ratio (95%CI): 1.26(1.08, 1.48), P = .004). Neither clinical variables nor biomarkers showed strong predictive ability for 3-year recipient survival. CONCLUSIONS: Plasma biomarkers in neurologically deceased donors were associated with organ use. SLPI enhanced prediction within a liver transplantation model, whereas IL-6 before transplantation was significantly associated with recipient 3-year survival. Clinicaltrials.gov: NCT00987714.

Serum alarm antiproteases in systemic sclerosis patients.

Alarm antiproteases, i.e. secretory leukocyte protease inhibitor ad elafin, are key mediators in innate immune response and integrate innate and adaptive immunity systems. The aim of the study was to assess clinical significance of serum levels of alarm antiproteases, elafin and secretory leukocyte protease inhibitor (SLPI) in patients with systemic sclerosis (SSc). Twenty-eight patients with SSc, 25 patients with rheumatoid arthritis (RA) and 22 healthy controls were recruited. Serum elafin and SLPI levels were examined using enzyme-linked immunosorbent assay (ELISA). The patients with SSc had significantly increased serum levels of SLPI in comparison with the RA patients and the healthy controls (p<0.01), and the RA patients presented significantly higher serum levels of elafin in comparison with the controls (p=0.003). In the SSc subgroup serum SLPI level negatively correlated with diffusing capacity of the lung for carbon monoxide (DLCO) (r=-0.41, p=0.03) and total lung capacity (r=-0.42, p=0.03). Both alarm antiproteases, elafin and SLPI could be potentially implicated in the pathogenesis of SSc and SLPI may be considered a candidate for serum biomarker of lung involvement in SSc.

Elevated Concentrations of SERPINE2/Protease Nexin-1 and Secretory Leukocyte Protease Inhibitor in the Serum of Patients with Papillary Thyroid Cancer.

Introduction. SERPINE2 and secretory leukocyte protease inhibitor (SLPI) are proteins with anticoagulant properties which could promote solid tumor growth. However, their role in the pathogenesis of thyroid cancer has not been determined. Materials and Methods. The aim of this study was to assess serum SERPINE2 and SLPI concentrations in a group of 36 patients with papillary thyroid cancer (PTC) and a group of 19 subjects with multinodular nontoxic goiter (MNG). The control group (CG) consisted of 20 healthy volunteers. Blood samples were collected one day before surgery. Serum SERPINE2 and SLPI concentrations were measured using specific ELISA methods. Results. Significantly higher concentrations of SERPINE2 and SLPI were found in patients with PTC as compared with MNG and controls. Positive correlation was found between SERPINE2 and SLPI concentrations in PTC patients. The levels of SERPINE2 and SLPI did not differ significantly between MNG and healthy controls. Conclusions. Our results indicate that SERPINE2 and SLPI play a significant role in the development of papillary thyroid cancer and imply that the evaluation of serum concentrations of both anticoagulant molecules may be considered as additional marker for the differentiation of malignancies during the preoperative diagnosis of patients with thyroid gland tumors.

Secretory leukocyte protease inhibitor is a survival and proliferation factor for castration-resistant prostate cancer.

Androgen receptor (AR)-mediated gene expression continues to have a critical role in promoting castration-resistant prostate cancer (CRPC) survival and growth even after androgen deprivation therapy. AR cistrome analyses in CRPC cells have identified a large number of AR target genes involved in proliferative and cell cycle-related functions, and hold promise for development of novel therapeutic approaches for CRPC. However, there is little understanding of how these genes function in vivo and what the clinical implications are. We previously reported that secretory leukocyte peptidase inhibitor (SLPI) is regulated by the AR in a ligand-independent manner in CRPC cells and required for CRPC cell proliferation under androgen-deprived conditions. SLPI is a secreted serine protease inhibitor, which is overexpressed in a number of cancers, including lung, breast and ovarian cancer, and involved in tumor progression. However, the oncogenic potential of SLPI in prostate cancer remains unknown. Here we provide the first evidence that SLPI is upregulated in a subset of CRPC cell lines and CRPC patient tumors. In addition, serum SLPI levels are significantly elevated in metastatic CRPC patients compared with hormone naive patients, raising the possibility that this could serve as a biomarker. We demonstrated that SLPI expression has functional significance, as it promotes CRPC cell survival and growth after androgen withdrawal in vivo and in vitro. Last, we demonstrated that the oncogenic effect of SLPI may be due to protection of growth factor progranulin from enzymatic cleavage or suppression of CRPC cell apoptosis independent of anti-protease activity of SLPI. These findings implicate SLPI as a potential biomarker of resistance to AR inhibition and therapeutic target for CRPC treatment.

Discovery of serum biomarkers of ovarian cancer using complementary proteomic profiling strategies.

PURPOSE: Ovarian cancer is a devastating disease and biomarkers for its early diagnosis are urgently required. Serum may be a valuable source of biomarkers that may be revealed by proteomic profiling. Herein, complementary serum protein profiling strategies were employed for discovery of biomarkers that could discriminate cases of malignant and benign ovarian cancer. EXPERIMENTAL DESIGN: Identically collected and processed serum samples from 22 cases of invasive epithelial ovarian cancer, 45 benign ovarian neoplasms, and 64 healthy volunteers were subjected to immunodepletion and protein equalization coupled to 2D-DIGE/MS and multidimensional fractionation coupled to SELDI-TOF profiling with MS/MS for protein identification. Selected candidates were verified by ELISA in samples from malignant (n = 70) and benign (n = 89) cases and combined marker panels tested against serum CA125. RESULTS: Both profiling platforms were complementary in identifying biomarker candidates, four of which (A1AT, SLPI, APOA4, VDBP) significantly discriminated malignant from benign cases. However, no combination of markers was as good as CA125 for diagnostic accuracy. SLPI was further tested as an early marker using prediagnosis serum samples. While it rose in cases toward diagnosis, it did not discriminate prediagnosis cases from controls. CONCLUSIONS AND CLINICAL RELEVANCE: The candidate biomarkers warrant further validation in independent sample sets.

The impact of IFN-γ receptor on SLPI expression in active tuberculosis: association with disease severity.

Interferon (IFN)-γ displays a critical role in tuberculosis (TB), modulating the innate and adaptive immune responses. Previously, we reported that secretory leukocyte protease inhibitor (SLPI) is a pattern recognition receptor with anti-mycobacterial activity against Mycobacterium tuberculosis (Mtb). Herein, we determined whether IFN-γ modulated the levels of SLPI in TB patients. Plasma levels of SLPI and IFN-γ were studied in healthy donors (HDs) and TB patients. Peripheral blood mononuclear cells from HDs and patients with TB or defective IFN-γ receptor 1* were stimulated with Mtb antigen and SLPI, and IFN-γR expression levels were measured. Both SLPI and IFN-γ were significantly enhanced in plasma from those with TB compared with HDs. A direct association between SLPI levels and the severity of TB was detected. In addition, Mtb antigen stimulation decreased the SLPI produced by peripheral blood mononuclear cells from HDs, but not from TB or IFN-γR patients. Neutralization of IFN-γ reversed the inhibition of SLPI induced by Mtb antigen in HDs, but not in TB patients. Furthermore, recombinant IFN-γ was unable to modify the expression of SLPI in TB patients. Finally, IFN-γR expression was lower in TB compared with HD peripheral blood mononuclear cells. These results show that Mtb-induced IFN-γ down-modulated SLPI levels by signaling through the IFN-γR in HDs. This inhibitory mechanism was not observed in TB, probably because of the low expression of IFN-γR detected in these individuals.

Cervical inflammation and immunity associated with hormonal contraception, pregnancy, and HIV-1 seroconversion.

OBJECTIVE: Hormonal contraception (HC), younger age, and pregnancy have been associated with increased HIV risk in some studies. We sought to elucidate the biological mechanisms for these associations. DESIGN: Case-control selection of specimens from a large, prospective, clinical study. METHODS: We enrolled and followed 4531 HIV-negative women from Uganda and Zimbabwe using either the injectable depo-medroxyprogesterone acetate (DMPA), combined oral contraception, or no HC (NH). Innate immunity mediators were measured in cervical samples collected from women at their visit before HIV seroconversion (n = 199) and matched visits from women remaining HIV uninfected (n = 633). Generalized linear models were applied after Box-Cox power transformation. RESULTS: Higher RANTES and lower secretory leukocyte protease inhibitor (SLPI) levels were associated with HIV seroconversion. DMPA users had higher RANTES and lower BD-2 levels. Most inflammation-promoting and/or inflammation-inducible mediators were higher [interleukin (IL)-1ß, IL-6, IL-8, MIP-3α, vascular endothelial growth factor, and SLPI], and the protective BD-2 and IL-1RA:IL-1ß ratio were lower among combined oral contraception users. Pregnant women showed a similar cervical immunity status (higher IL-1ß, IL-6, IL-8, vascular endothelial growth factor, SLPI, and IL-1RA; lower IL-1RA:IL-1ß). Age <25 years was associated with lower SLPI, IL-8, MIP-3α but higher IL-1RA:IL-1ß. Zimbabwean women (with higher HIV seroconversion rates) had overall higher pro-inflammatory and lower anti-inflammatory protein levels than Ugandan women. CONCLUSIONS: HC use, pregnancy, and young age alter cervical immunity in different ways known to increase risk of HIV, for example, through increased levels of pro-inflammatory cytokines or decreased levels of SLPI. Higher levels of RANTES may be one factor underlying a possible association between DMPA use and risk of HIV acquisition.

Secretory leukocyte protease inhibitor protein regulates the penetrance of frontotemporal lobar degeneration in progranulin mutation carriers.

The discovery that mutations in the gene encoding for progranulin (GRN) cause frontotemporal lobar degeneration (FTLD) and other neurodegenerative diseases leading to dementia has brought renewed interest in progranulin and its functions in the central nervous system. Full length progranulin is preserved from cleavage by secretory leukocyte protease inhibitor (SLPI), one of the smallest serine protease inhibitor circulating in plasma. Herein, we investigated the relationship between circulating SLPI and progranulin in affected and unaffected subjects belonging to 26 Italian pedigrees carrying GRN null mutations. In GRN null mutation carriers, we demonstrated: i) an increase of circulating SLPI levels in affected subjects; ii) an age-related upregulation of the serine-protease inhibitor in response to lifetime progranulin shortage; and iii) a delay in the age of onset in subjects with the highest SLPI protein levels. The study of SLPI and its relation to progranulin suggests the existence of unexpected molecular players in progranulin-associated neurodegeneration.

Secretory leukocyte protease inhibitor: a pivotal mediator of anti-inflammatory responses in acetaminophen-induced acute liver failure.

UNLABELLED: Acetaminophen-induced acute liver failure (AALF) is characterized both by activation of innate immune responses and susceptibility to sepsis. Circulating monocytes and hepatic macrophages are central mediators of inflammatory responses and tissue repair processes during human AALF. Secretory leukocyte protease inhibitor (SLPI) modulates monocyte/macrophage function through inhibition of nuclear factor kappa B (NF-κB) signaling. The aims of this study were to establish the role of SLPI in AALF. Circulating levels of SLPI, monocyte cluster of differentiation 163 (CD163), human leukocyte antigen-DR (HLA-DR), and lipopolysaccharide (LPS)-stimulated levels of NF-κBp65, tumor necrosis factor alpha (TNF-α) and interleukin (IL)-6 were determined in patients with AALF, chronic liver disease, and healthy controls. Immunohistochemistry and multispectral imaging of AALF explant tissue determined the cellular sources of SLPI and hepatic macrophage phenotype. The phenotype and function of monocytes and macrophages was determined following culture with recombinant human (rh)-SLPI, liver homogenates, and plasma derived from AALF patients in the presence and absence of antihuman (α)SLPI. Hepatic and circulatory concentrations of SLPI were elevated in AALF and immunohistochemistry revealed SLPI expression in biliary epithelial cells and within hepatic macrophages (h-mψ) in areas of necrosis. H-mψ and circulating monocytes in AALF exhibited an anti-inflammatory phenotype and functional characteristics; typified by reductions in NF-κBp65, TNF-α, and IL-6 and preserved IL-10 secretion following LPS challenge. Culture of healthy monocytes with AALF liver homogenates, plasma, or rhSLPI induced monocytes with strikingly similar anti-inflammatory characteristics which were reversed by inhibiting the activity of SLPI. CONCLUSION: SLPI is a pivotal mediator of anti-inflammatory responses in AALF through modulation of monocyte/macrophage function, which may account for the susceptibility to sepsis in AALF.

Utility of progranulin and serum leukocyte protease inhibitor as diagnostic and prognostic biomarkers in ovarian cancer.

BACKGROUND: Epithelial ovarian cancer (EOC) is the fifth leading cause of cancer-related death in females and leading gynecologic cause of cancer-related death. Despite the identification of a number of serum biomarkers, methods to identify early-stage disease and predict prognosis remain scarce. We have evaluated two biologically connected serum biomarkers, serum leukocyte protease inhibitor (SLPI) and progranulin (PGRN). METHODS: Two-hundred frozen plasma samples were acquired from the Mayo Clinic Biospecimen Repository for Ovarian Cancer Research. Samples were obtained from 50 patients with benign conditions, 50 with American Joint Committee on Cancer (AJCC) stage I and II EOC, and 100 with AJCC stage III and IV EOC. Samples were obtained before surgical resection of a mass and were analyzed for absolute levels of SLPI and PGRN using ELISA assays. Receiver-operator characteristic curves were generated for SLPI and PGRN. Median follow-up was 48 months. RESULTS: Absolute levels of SLPI were significantly elevated in patients with EOC compared with benign disease and predicted the presence of EOC (AUC of 0.812; P = 0.04); SLPI remained elevated in the subset of patients with normal CA-125. PGRN levels were not significantly increased in patients with early-stage or late-stage EOC as a whole, but an increase in PGRN levels was associated with decreased overall survival in advanced EOC. CONCLUSIONS: SLPI levels are elevated in EOC, and SLPI shows promise as a diagnostic biomarker for patients with both elevated and normal CA-125 levels. An increase in PGRN is associated with decreased overall survival. IMPACT: SLPI is elevated in EOC and warrants investigation in a screening study in women at risk for EOC.

[Pathogenetic substantiation of using peptidases in the treatment of patients with generalized periodontitis].

76 patients of whom 52 patients with GP-II degree exacerbative and 24 somatically healthy people aged 20-50 years were studied. Based on these immunological examination serapeptydase was assigned per os, as a complementary product to the basic therapy. Any concentration of secretory leukocyte protease inhibitor (SLPI) indicates the dominant hyperergic inflammation in periodontal tissues, accompanied by increased proteolysis. Profitable accumulation in the serum of patients with GP inhibitors proteinase to 53%, IL-1beta - to 26.3%, IL-2 - to 19.5%, IL-8 - to 42.8% FNPalpha - up to 48.3%, and reduction of IFNalpha to 78.1% indicates changes of complex "protease-antiproteases" immunocompetent cells and activation of inflammatory processes at the local and systemic levels.

Antimicrobial peptide plasma concentrations in patients with community-acquired pneumonia.

BACKGROUND: Community-acquired pneumonia (CAP) is a common and potentially life-threatening infection. Innate immunity is the first line of defence, and antimicrobial peptides (AMPs) produced by white blood cells and at epithelial barriers participate by killing microorganisms and neutralizing bacterial toxins. We wanted to investigate whether concentrations of AMPs (1) are increased in CAP, (2) predict the clinical outcome, and (3) differ depending on the causative microbe. METHODS: Plasma concentrations of AMPs were measured using an enzyme-linked immunosorbent assay in 89 patients with CAP, 21 patients with non-respiratory tract infections (non-RTI), and 63 healthy control subjects. RESULTS: In subjects with CAP, mean plasma concentrations of secretory leukocyte protease inhibitor (SLPI) and bactericidal/ permeability-increasing protein (BPI) were significantly higher than in healthy control subjects (85 vs 45 ng/ml, p < 0.001 and 48 vs 10 ng/ml, p < 0.001, respectively), but less markedly increased in patients with non-RTI (68 ng/ml, p = 0.06 and 41 ng/ml, p = 0.43). LL-37 and human neutrophil peptides 1-3 (HNP 1-3) levels were not increased in subjects with CAP. Levels of BPI and SLPI did not correlate to severity of disease, and AMP levels did not differ depending on the causative agent. Interestingly, male subjects with CAP displayed increased concentrations of SLPI compared to females. This was not observed in subjects with non-RTI and healthy control subjects. CONCLUSIONS: Subjects with CAP showed increased plasma concentrations of SLPI and BPI compared to healthy control subjects. The finding of higher SLPI levels in male subjects with CAP implies that there are sex-dependent immunological differences in SLPI turnover.

Sulforaphane induces SLPI secretion in the nasal mucosa.

Cells lining the respiratory tract are equipped with mechanisms that dampen the effects of oxidative stress. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is a mediator involved in regulating oxidative stress. Recent data indicate Nrf2 also controls expression of secretory leukocyte protease inhibitor (SLPI). Sulforaphane (SFN), an isothiocyanate found in cruciferous vegetables, enhances Nrf2 activity. Therefore, we hypothesized that SFN supplementation induces SLPI secretion in the nasal mucosa in an Nrf2 dependent manner. Healthy nonsmoking adults ingested SFN-containing broccoli shake homogenate (BSH) for 3 consecutive days. Nasal lavage fluid (NLF) was collected before and after BSH ingestion and analyzed for SLPI protein levels. In follow up in vitro experiments, differentiated primary nasal epithelial cells were used to evaluate the relationship between SFN, Nrf2, and SLPI. Epithelial cells were transduced with Nrf2-specific shRNA to examine the regulatory role of Nrf2 on SLPI expression. Supplementation with BSH significantly increased SLPI levels in NLF. SFN supplementation in vitro significantly enhanced SLPI secretion and these effects were significantly decreased in cells transduced with Nrf2-specific shRNA. Our data support a relationship between nutritional supplementation, Nrf2 activation, and SLPI secretion. Therefore, ingestion of SFN-containing foods has therapeutic potential to augment SLPI expression in the nasal mucosa.

Clinical significance of serum levels of secretory leukocyte protease inhibitor in patients with systemic sclerosis.

We aimed to investigate the clinical significance of serum levels of secretory leukocyte protease inhibitor (SLPI), which is widely expressed in lung tissues and serves as a useful marker reflecting the activity of various lung diseases, in patients with systemic sclerosis (SSc). Serum SLPI levels were measured by a specific enzyme-linked immunosorbent assay (ELISA) in 58 SSc patients and 16 healthy controls. Serum SLPI levels in diffuse cutaneous SSc and in limited cutaneous SSc with interstitial lung disease (ILD) were significantly higher than those in healthy controls (43.1 ± 18.4 vs. 30.9 ± 3.76 ng/ml, p < 0.05 and 39.8 ± 10.3 vs. 30.9 ± 3.76 ng/ml, p < 0.01, respectively). The incidences of decreased percent diffusing capacity for carbon monoxide (%DLco) and decreased percent vital capacity (%VC) were significantly greater in SSc patients with elevated SLPI levels than in those with normal levels (73 vs. 31%, p < 0.01 and 24 vs. 4%, p < 0.05, respectively). Furthermore, serum SLPI levels were inversely correlated with %DLco (r = -0.40, p < 0.01), while they were positively correlated with surfactant protein D (r = 0.28, p < 0.05). Longitudinal study revealed the association of serum SLPI levels with the disease activity of SSc-ILD. SLPI serves as a useful serum marker for evaluating SSc-ILD.

Molecular mechanisms of inflammation during exacerbations of chronic obstructive pulmonary disease.

INTRODUCTION: Exacerbations of chronic obstructive pulmonary disease (COPD) are characterised by an inflammatory and systemic response that persists for some time after their clinical resolution. The mechanisms of this inflammatory process are not well known. OBJECTIVES: To explore the inflammatory changes and possible mechanisms during COPD exacerbation. METHODS: We determined the inflammatory cell concentrations in blood and sputum, nitric oxide in exhaled air (FeNO), C-reactive protein (CRP) in plasma, cytokines (IL-6, 8, 1ß, 10, 12, TNF-α) and SLPI (leukocyte protease inhibitor) and total antioxidant status (TAS) in blood and sputum, the activity of nuclear kappa B factor (NF-κ B) and of the histone deacetylase enzyme (HDAC) in 17 patients during COPD exacerbation and in stable phase, as well as in 17 smoker and 11 non-smoker controls. RESULTS: COPD exacerbations are characterised by high levels of FeNO (p<0.05), plasma CRP (p<0.001) and IL-8, IL-1B, IL-10 in sputum (p<0.05) greater activation of NF-κ appaB in sputum macrophages compared with stable COPD and controls. During the stable phase, there continue to be high levels of oxidative stress, SLPI, IL-8, IL-6 and TNF-alfa, with no observed changes in either HDAC activity or in the amount of neutrophils in sputum, despite presenting a significant improvement (p<0.05) in lung function. CONCLUSIONS: Changes were observed in different pulmonary and systemic inflammatory markers during COPD exacerbation, which did not completely resolve during stable phase. However, current treatment does not allow for HDAC activity to be modified, which limits its anti-inflammatory effects.

The alarm secretory leukocyte protease inhibitor increases with progressive metabolic dysfunction.

BACKGROUND: Secretory leukocyte protease inhibitor (SLPI) is an alarm antiprotease secreted by neutrophils and mucous membranes that potently inhibits the inflammatory cascade; however, the role of SLPI in human disease remains largely unknown. We hypothesized that SLPI is related to chronic low-grade inflammatory diseases, such as metabolic syndrome (MS) or type-2 diabetes (T2DM). METHODS: We examined associations between circulating SLPI (ELISA) and quantitative traits of MS (ATPIII criteria) in 261 Caucasian men with various degrees of metabolic dysfunction. Subjects had neither MS nor T2DM (n=140), either diagnosis (n=44) or both diagnoses (n=77). RESULTS: Circulating SLPI increased with progressive metabolic dysfunction, with a mean increase of 4.4 ng/ml (95% IC 2.4 to 6.3 ng/ml; p<0.001) for each unit increase in the criteria used to define MS. Circulating SLPI showed independent associations with uric acid [ß=5.1 (95% CI 3.4 to 6.7), p<0.00001], serum lipids, pulse pressure and inflammatory markers. CONCLUSIONS: Circulating SLPI increases with progressive metabolic dysfunction and is related to metabolic and inflammatory parameters in men.

Multiplexed homogeneous proximity ligation assays for high-throughput protein biomarker research in serological material.

A high throughput protein biomarker discovery tool has been developed based on multiplexed proximity ligation assays in a homogeneous format in the sense of no washing steps. The platform consists of four 24-plex panels profiling 74 putative biomarkers with sub-pm sensitivity each consuming only 1 µl of human plasma sample. The system uses either matched monoclonal antibody pairs or the more readily available single batches of affinity purified polyclonal antibodies to generate the target specific reagents by covalently linking with unique nucleic acid sequences. These paired sequences are united by DNA ligation upon simultaneous target binding forming a PCR amplicon. Multiplex proximity ligation assays thereby converts multiple target analytes into real-time PCR amplicons that are individually quantified using microfluidic high capacity qPCR in nano liter volumes. The assay shows excellent specificity, even in multiplex, by its dual recognition feature, its proximity requirement, and most importantly by using unique sequence specific reporter fragments on both antibody-based probes. To illustrate the potential of this protein detection technology, a pilot biomarker research project was performed using biobanked plasma samples for the detection of colorectal cancer using a multivariate signature.