Calcium-dependent secretion in human neutrophils: a proteomic approach

Calprotectin as a diagnostic marker for sepsis: A meta-analysis

Introduction

Sepsis is a life-threatening condition, and biomarkers are needed to diagnose sepsis fast and accurately. We aimed to perform this meta-analysis to investigate the diagnostic value of calprotectin on sepsis in critically ill patients.

Methods

The investigators searched MEDLINE, Embase, Web of Science and Cochrane Library. Studies were included if they assessed the diagnostic accuracy of serum calprotectin for sepsis in intensive care unit (ICU). We estimated its diagnostic value and explored the source of heterogeneity. The bivariate model and the hierarchical summary receiver operating characteristic (HSROC) curve were used in the meta-analysis.

Results

Six records assessing 821 patients were included in this meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio (PLR), and diagnostic odds ratio (DOR) were separately as 0.77, 0.85, 5.20, 0.27, respectively. The Fagan's nomogram showed post-test probabilities of 91% and 35% for positive and negative outcomes, respectively. Subgroup analysis indicated that sepsis definition could be a possible source of heterogeneity, but there's no sufficient data to investigate sepsis-3 definition. Sensitivity analysis suggested that two studies could affect the stability of pooled results.

Conclusion

On the basis of our meta-analysis, calprotectin is a helpful marker for early diagnosis of sepsis on ICU admission.

Synovial fluid calprotectin performs better than synovial fluid polymerase chain reaction and interleukin-6 in the diagnosis of periprosthetic joint infection : a systematic review and meta-analysis

AIMS

The preoperative diagnosis of periprosthetic joint infection (PJI) remains a challenge due to a lack of biomarkers that are both sensitive and specific. We investigated the performance characteristics of polymerase chain reaction (PCR), interleukin-6 (IL6), and calprotectin of synovial fluid in the diagnosis of PJI.

METHODS

We performed systematic search of PubMed, Embase, The Cochrane Library, Web of Science, and Science Direct from the date of inception of each database through to 31 May 2021. Studies which described the diagnostic accuracy of synovial fluid PCR, IL6, and calprotectin using the Musculoskeletal Infection Society criteria as the reference standard were identified.

RESULTS

Overall, 31 studies were identified: 20 described PCR, six described IL6, and five calprotectin. The sensitivity and specificity were 0.78 (95% confidence interval (CI) 0.67 to 0.86) and 0.97 (95% CI 0.94 to 0.99), respectively, for synovial PCR;, 0.86 (95% CI 0.74 to 0.92), and 0.94 (95% CI 0.90 to 0.96), respectively, for synovial IL6; and 0.94 (95% CI 0.82 to 0.98) and 0.93 (95% CI 0.85 to 0.97), respectively, for synovial calprotectin. Likelihood ratio scattergram analyses recommended clinical utility of synovial fluid PCR and IL6 as a confirmatory test only. Synovial calprotectin had utility in the exclusion and confirmation of PJI.

CONCLUSION

Synovial fluid PCR and IL6 had low sensitivity and high specificity in the diagnosis of PJI, and is recommended to be used as confirmatory test. In contrast, synovial fluid calprotectin had both high sensitivity and specificity with utility in both the exclusion and confirmation of PJI. We recommend use of synovial fluid calprotectin studies in the preoperative workup of PJI. Cite this article: Bone Joint J 2022;104-B(3):311-320.

Metallo-β-lactamases in the Age of Multidrug Resistance: From Structure and Mechanism to Evolution, Dissemination, and Inhibitor Design

Antimicrobial resistance is one of the major problems in current practical medicine. The spread of genes coding for resistance determinants among bacteria challenges the use of approved antibiotics, narrowing the options for treatment. Resistance to carbapenems, last resort antibiotics, is a major concern. Metallo-β-lactamases (MBLs) hydrolyze carbapenems, penicillins, and cephalosporins, becoming central to this problem. These enzymes diverge with respect to serine-β-lactamases by exhibiting a different fold, active site, and catalytic features. Elucidating their catalytic mechanism has been a big challenge in the field that has limited the development of useful inhibitors. This review covers exhaustively the details of the active-site chemistries, the diversity of MBL alleles, the catalytic mechanism against different substrates, and how this information has helped developing inhibitors. We also discuss here different aspects critical to understand the success of MBLs in conferring resistance: the molecular determinants of their dissemination, their cell physiology, from the biogenesis to the processing involved in the transit to the periplasm, and the uptake of the Zn(II) ions upon metal starvation conditions, such as those encountered during an infection. In this regard, the chemical, biochemical and microbiological aspects provide an integrative view of the current knowledge of MBLs.

S100A8/A9 in Myocardial Infarction: A Promising Biomarker and Therapeutic Target

Myocardial infarction (MI), the main cause of cardiovascular-related deaths worldwide, has long been a hot topic because of its threat to public health. S100A8/A9 has recently attracted an increasing amount of interest as a crucial alarmin that regulates the pathogenesis of cardiovascular disease after its release from myeloid cells. However, the role of S100A8/A9 in the etiology of MI is not well understood. Here, we elaborate on the critical roles and potential mechanisms of S100A8/A9 driving the pathogenesis of MI. First, cellular source of S100A8/A9 in infarcted heart is discussed. Then we highlight the effect of S100A8/A9 heterodimer in the early inflammatory period and the late reparative period of MI as well as myocardial ischemia/reperfusion (I/R) injury. Moreover, the predictive value of S100A8/A9 for the risk of recurrence of cardiovascular events is elucidated. Therefore, this review focuses on the molecular mechanisms of S100A8/A9 in MI pathogenesis to provide a promising biomarker and therapeutic target for MI.

Regulatory T cells in Crohn's disease following anti-TNF-α therapy

BACKGROUND AND AIM

Anti-tumor necrosis factor alpha (TNF-α) therapy is an effective therapy for Crohn's disease (CD). We investigated FoxP3⁺ and CD127^- regulatory T cells (Tregs) before and after administration of anti-TNF-α therapy in CD.

METHODS

Eight patients with active CD who had received anti-TNF-α antibodies were enrolled. Treatment responses were followed by physical examination and Crohn's disease activity index (CDAI) scoring before and 2 weeks after the initial administration of anti-TNF-α antibodies. Peripheral blood samples were collected before and 2 weeks after treatment. White blood cell count and serum levels of C-reactive protein (CRP) and albumin were measured. FoxP3⁺ expression and CD127^- Tregs were measured by fluorescence activated cell sorting (FACS) analysis of whole blood samples.

RESULTS

Median values of CDAI decreased significantly after treatment. The proportion of FoxP3⁺ Tregs increased significantly after treatment. There was a significant negative correlation between ΔCD127^- Tregs and Δlymphocyte.

CONCLUSIONS

Anti-TNF-α therapy would enhance Tregs, which may account for the mechanism underlying the positive effect of the anti-TNF-α treatment in CD patients.

Increased levels of calprotectin in the saliva of patients with geographic tongue

OBJECTIVE

We investigated whether patients with geographic tongue have increased salivary levels of calprotectin and whether there is a correlation between the salivary levels of calprotectin and interleukin 8 (IL-8), which is another marker of inflammation.

METHODS

Twenty-three patients diagnosed with geographic tongue and 32 control subjects without oral mucosal lesions were included in the study. The patients with geographic tongue were classified based on clinical appearance and number of oral lesions. ELISAs were used to determine the levels of calprotectin and IL-8 in whole saliva samples.

RESULTS

There was a statistically significant increase in the salivary output of calprotectin in patients with geographic tongue compared with the healthy controls (62 ± 9,1 vs. 37,5 ± 4,7 µg/min; p = .0134). Furthermore, the levels of calprotectin correlated positively with the number of oral lesions in patients with geographic tongue. There was also a significant and positive correlation between the salivary levels of calprotectin and IL-8, both for the patients with geographic tongue and the controls.

CONCLUSION

This study supports the notion that GT is an inflammatory disease, in which the activation of neutrophils and production of calprotectin in the saliva may play roles in its pathogenesis.

Biomarkers for oralization during long-term proton pump inhibitor therapy predict survival in cirrhosis

Proton pump inhibitors (PPI) are an invaluable therapy option for acid related diseases; however, PPI therapy is also linked to a series of side effects in cirrhosis, such as microbiome alterations, spontaneous bacterial peritonitis and hepatic encephalopathy. Decision tools to balance benefits and risks of PPI therapy are largely missing. In this study, we tested gut-derived biomarkers to identify PPI-associated dysbiosis, its association with gut barrier function and liver-related mortality. In this observational study, faecal microbiome composition data obtained from 16S rDNA sequencing of 90 cirrhotic patients with and without long-term PPI use and additional potential biomarkers identified from the literature were evaluated for their predictive value regarding PPI-associated dysbiosis and liver-related three-year mortality. In addition, faecal calprotectin, faecal zonulin and serum lipopolysaccharides were assessed as markers for intestinal inflammation, gut permeability and bacterial translocation. Streptococcus salivarius, Veillonella parvula and the genus Streptococcus were significantly increased in patients with long-term PPI therapy and performed well as biomarkers for PPI-associated dysbiosis (accuracy: 74%, 72% and 74%, respectively). The abundance of Streptococcus salivarius was linked to intestinal inflammation and gut barrier dysfunction, whereas the abundance of Veillonella parvula showed associations with liver disease severity; both were independent predictors for liver-related three-year mortality. Gut-derived biomarkers of PPI-associated dysbiosis are linked to worse outcome and a potential option to evaluate the risks of adverse events during long-term PPI therapy.

A novel prognostic biomarker for recurrent aphthous stomatitis: calprotectin

OBJECTIVE

This study aims to investigate whether there is a correlation between serum calprotectin concentration and oral ulcer activity in patients with active recurrent aphthous stomatitis.

METHOD

This prospective, cross-sectional, historical cohort study included 52 patients (26 with active lesions and 26 with inactive lesions) with recurrent aphthous stomatitis and 27 healthy volunteers. The relationship between the groups was statistically evaluated in terms of serum calprotectin level and other inflammatory parameters.

RESULTS

The median calprotectin value of the active lesion group (80.5 ng/ml) was significantly higher than that of the control group (55.4 ng/ml, p = 0.002). Furthermore, the median calprotectin value of the active lesion group was significantly higher than that of the inactive lesion group (72.5 ng/ml, p = 0.017).

CONCLUSION

In patients with recurrent aphthous stomatitis and active ulcer lesions, the serum calprotectin value can be used as a reliable and robust prognostic marker for inflammation.

Association of A-197G polymorphism in interleukin-17 gene with chronic periodontitis: Evidence from six case-control studies with a computational biology approach

AIM

The aim of the present study was to evaluate the association of interleukin-17 (IL-17) A-197G gene polymorphism with chronic periodontitis (CP) in a case-control study, a meta-analysis, and an in silico approach.

METHODS

In the case-control study, 122 cases with CP and 126 healthy controls were recruited; IL-17 A-197G genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism. In the meta-analysis, comprehensive literature retrieval was performed on valid databases to identify relevant studies. Bioinformatics tools were employed to investigate the effects of A-197G transition on the promoter region of IL-17.

RESULTS

Our case-control study revealed a significant association between IL-17 A-197G transition and CP. The overall meta-analysis revealed significant associations between the IL-17 A-197G polymorphism and CP risk in homozygote co-dominant and recessive models. The stratified analysis also showed a statistically significant association between the mentioned transition and CP risk in the Caucasian population. The in silico analysis revealed that the A-197G polymorphism could make changes in protein-binding sites of the IL-17 promoter region.

CONCLUSIONS

Our study supports that IL-17 A-197G transition could be a genetic risk factor for CP. However, further studies with a larger sample size among different ethnicities are required to obtain a more accurate conclusion.

Hydroxychloroquine modulates elevated expression of S100 proteins in systemic lupus erythematosus

Objectives

We investigated the effect of hydroxychloroquine (HCQ) on S100A8 and S100A9 serum levels in systemic lupus erythematosus (SLE) patients with low disease activity receiving immunosuppressants.

Methods

SELENA-SLEDAI, Cutaneous Lupus Erythematous Disease Area and Severity Index (CLASI) and serum levels of complement factors, anti-dsDNA antibodies, and white blood cell, lymphocyte, and platelet counts were used to evaluate disease activity, cutaneous disease activity, and immunological activity, respectively. Serum S100A8 and S100A9 were measured at HCQ administration and after 3 or 6 months using ELISA.

Results

S100A8 and S100A9 serum levels were elevated at baseline and the magnitude of decrease from baseline at 3 and 6 months after HCQ administration was greater in patients with renal involvement than in those without (baseline: S100A8, p = 0.034; S100A9, p = 0.0084; decrease: S100A8, p = 0.049; S100A9, p = 0.023). S100 modulation was observed in patients with ( n = 17; S100A8, p = 0.0011; S100A9, p = 0.0002) and without renal involvement ( n = 20; S100A8, p = 0.0056; S100A9, p = 0.0012), and was more apparent in patients with improved CLASI activity scores (improved: S100A8, p = 0.013; S100A9, p = 0.0032; unimproved: S100A8, p = 0.055; S100A9, p = 0.055). No associations were observed for immunological biomarkers.

Conclusion

HCQ may improve organ involvement in SLE by modulating S100 protein levels, especially in patients with renal or skin involvement.

The Role of Biomarkers in Clinical Trials of Inflammatory Bowel Disease

Clinical trials require valid outcome measures to assess the therapeutic benefit of investigational agents. Recently, regulatory authorities have mandated the use of patient-reported outcomes in combination with an objective measure of disease activity as primary outcome measures in inflammatory bowel disease trials. Endoscopy has commonly fulfilled the latter role; however, due to the costs and complexity of these assessments, interest has emerged in the use of noninvasive biomarkers. The role of C-reactive protein, fecal calprotectin, and fecal lactoferrin in clinical research is discussed.

S100A12 is up-regulated in pulmonary tuberculosis and predicts the extent of alveolar infiltration on chest radiography: an observational study

Pulmonary tuberculosis (PTB) results in lung functional impairment and there are no surrogate markers to monitor the extent of lung involvement. We investigated the clinical significance of S100A12 and soluble receptor for advanced glycation end-products (sRAGE) for predicting the extent of lung involvement. We performed an observational study in India with 119 newly diagnosed, treatment naïve, sputum smear positive, HIV-negative PTB patients and 163 healthy controls. All patients were followed-up for six months. Sociodemographic variables and the serum levels of S100A12, sRAGE, esRAGE, HMGB-1, TNF-α, IFN-γ and CRP were measured. Lung involvement in PTB patients was assessed by chest radiography. Compared with healthy controls, PTB patients had increased serum concentrations of S100A12 while sRAGE was decreased. S100A12 was an independent predictor of disease occurrence (OR 1.873, 95%CI 1.212-2.891, p = 0.004). Under DOTS therapy, S100A12 decreased significantly after 4 months whereas CRP significantly decreased after 2 months (p < 0.0001). Importantly, although CRP was also an independent predictor of disease occurrence, only S100A12 was a significant predictor of lung alveolar infiltration (OR 2.60, 95%CI 1.35-5.00, p = 0.004). These results suggest that S100A12 has the potential to assess the extent of alveolar infiltration in PTB.

Elevated expressions of myeloid-related proteins-8 and -14 are danger biomarkers for lupus nephritis

Myeloid-related proteins, MRP-8 and -14, which have been identified as molecules that mediate the danger signaling in innate immune response, are also known as the DAMPs (damage associated molecular pattern molecules). The proteins were found in infiltrating macrophages and neutrophils at inflammatory sites. Their expression was correlated with severe forms of glomerulonephritis. Therefore, this study examined whether or not MRP-8 and -14 can be used as biomarkers for identifying severely active lupus nephritis (LN). Total blood leukocyte samples and renal biopsy tissues from a prospective cohort of LN patients were used to determine mRNA and protein expression levels of MRP-8 and -14. The mRNA levels of MRP-8 and -14 in total blood leukocytes were significantly higher in active LN patients than quiescent LN patients and healthy controls. Moreover, the mRNA levels of MRP-8 and -14 in the total blood leukocytes and kidney tissues were significantly correlated with therapeutic response and the mRNA expression levels in the kidney were associated with an early loss of the kidney function. MRP-8 and -14 can be used as non-invasive prognostic biomarkers in patients with LN.

Fecal calprotectin concentrations in healthy children aged 1-18 months

Objective

Fecal calprotectin (FC) is an established biomarker of gut inflammation. The aim of this study was to evaluate FC concentrations in healthy children between 1 and 18 months of age.

Methods

Healthy children aged 1-18 months were enrolled in this study at the Department of Children's Health Care in Shanghai, China. Children’s stool samples were collected and analyzed, and FC concentration was determined using a commercially available enzyme-linked immunosorbent assay (ELISA). The children's weights and lengths were measured. Parents were asked to complete a brief questionnaire regarding several clinical and sociodemographic factors.

Results

The FC concentrations were unevenly distributed; the median FC concentration was 174.3 μg/g (range: 6.0-1097.7 μg/g) or 2.241 log10 μg/g (range: 0.775-3.041 log10 μg/g) for all 288 children. The children were divided into several age groups: 1-3 months, 3-6 months, 6-9 months, 9-12 months and 12-18 months. The median FC concentrations for these age groups were 375.2 μg/g (2.574 log10 μg/g), 217.9 μg/g (2.338 log10 μg/g), 127.7 μg/g (2.106 log10 μg/g), 96.1 μg/g (1.983 log10 μg/g) and 104.2 μg/g (2.016 log10 μg/g), respectively. A significant correlation between age and FC concentration was found (r=-0.490, p<0.001). A simple correlation analysis of weight-for-length Z-scores or weight-for-age Z-scores vs. FC concentrations showed that these variables were negatively correlated (Spearman’s rho=-0.287, p<0.001; Spearman’s rho=-0.243, p<0.001, respectively).

Conclusions

The FC levels of children aged 1-18 months exhibit a downward trend with increasing age and are greater than the normal levels observed in healthy adults. In healthy children aged <6 months, FC levels are high. In children aged 6-18 months, FC concentrations are relatively low but are still higher than those of children aged >4 years.

Keeping track of the growing number of biological functions of chitin and its interaction partners in biomedical research

Chitin is a vital polysaccharide component of protective structures in many eukaryotic organisms but seems absent in vertebrates. Chitin or chitin oligomers are therefore prime candidates for non-self-molecules, which are recognized and degraded by the vertebrate immune system. Despite the absence of polymeric chitin in vertebrates, chitinases and chitinase-like proteins (CLPs) are well conserved in vertebrate species. In many studies, these proteins have been found to be involved in immune regulation and in mediating the degradation of chitinous external protective structures of invading pathogens. Several important aspects of chitin immunostimulation have recently been uncovered, advancing our understanding of the complex regulatory mechanisms that chitin mediates. Likewise, the last few years have seen large advances in our understanding of the mechanisms and molecular interactions of chitinases and CLPs in relation to immune response regulation. It is becoming increasingly clear that their function in this context is not exclusive to chitin producing pathogens, but includes bacterial infections and cancer signaling as well. Here we provide an overview of the immune signaling properties of chitin and other closely related biomolecules. We also review the latest literature on chitinases and CLPs of the GH18 family. Finally, we examine the existing literature on zebrafish chitinases, and propose the use of zebrafish as a versatile model to complement the existing murine models. This could especially be of benefit to the exploration of the function of chitinases in infectious diseases using high-throughput approaches and pharmaceutical interventions.

The neutrophil protein S100A12 is associated with a comprehensive ultrasonographic synovitis score in a longitudinal study of patients with rheumatoid arthritis treated with adalimumab

Background

The calcium-binding protein S100A12 correlates with measures of disease activity in patients with rheumatoid arthritis (RA). The protein reflects neutrophil activation and the present objective was to explore in a pilot study the associations between S100A12 and other inflammatory markers, clinical assessments as well as degree of synovitis detected by a comprehensive ultrasonography (US) examination in RA patients during biologic treatment.

Methods

Twenty patients with RA were examined clinically and by use of US as well as laboratory markers S100A12, calprotectin, C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) before starting adalimumab, with follow-up after 1, 3, 6 and 12 months. Ultrasonographic B-mode (BM) and power Doppler (PD) assessments of 78 joints, 36 tendons/tendon groups and 2 bursas were performed, and sum US scores calculated. Wilcoxon signed rank test assessed treatment response and Spearman rank correlation test was used to calculate correlations.

Results

The concentrations of S100A12 decreased after 3 months (p < 0.01) and significant correlations were found between S100A12 and the other laboratory markers during follow-up (0.50-0.62, p < 0.05). Of the clinical assessments, S100A12 had highest correlations with the assessor’s global VAS (0.46-0.85, p < 0.05). Compared with CRP and ESR, S100A12 showed higher correlations with the sum US scores (both BM and PD), with median (range) correlation coefficients of 0.55 (0.35-0.78 (NS-p < 0.001)) for sum BM scores and 0.45 (0.27-0.75 (NS-p < 0.001)) for sum PD scores.

Conclusions

The S100A12 protein was significantly associated with other inflammatory markers, clinical assessments as well as sum US scores, indicating that S100A12 is a potential marker of inflammation in RA patients.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2474-15-335) contains supplementary material, which is available to authorized users.

High prevalence of chitotriosidase deficiency in Peruvian Amerindians exposed to chitin-bearing food and enteroparasites

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Catalytic deficiency of chitotriosidase has a very high frequency in Amerindians highly exposed to chitin from enteroparasites and diet.

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Mutation frequencies are similar to those found in East Asian populations, and is probably conserved for a founder effect.

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Such condition precludes the use of CHIT1 as a disease biomarker in South American populations with strong ethnic ancestry.

The human genome encodes a gene for an enzymatically active chitinase (CHIT1) located in a single copy on Chromosome 1, which is highly expressed by activated macrophages and in other cells of the innate immune response. Several dysfunctional mutations are known in CHIT1, including a 24-bp duplication in Exon 10 causing catalytic deficiency. This duplication is a common variant conserved in many human populations, except in West and South Africans. Thus it has been proposed that human migration out of Africa and the consequent reduction of exposure to chitin from environmental factors may have enabled the conservation of dysfunctional mutations in human chitinases. Our data obtained from 85 indigenous Amerindians from Peru, representative of populations characterized by high prevalence of chitin-bearing enteroparasites and intense entomophagy, reveal a very high frequency of the 24-bp duplication (47.06%), and of other single nucleotide polymorphisms which are known to partially affect enzymatic activity (G102S: 42.7% and A442G/V: 25.5%). Our finding is in line with a founder effect, but appears to confute our previous hypothesis of a protective role against parasite infection and sustains the discussion on the redundancy of chitinolytic function.

The rational design of specific peptide inhibitor against p38α MAPK at allosteric-site: a therapeutic modality for HNSCC

p38α is a significant target for drug designing against cancer. The overproduction of p38α MAPK promotes tumorigenesis in head and neck squamous cell carcinoma (HNSCC). The ATP binding and an allosteric site referred as DFG are the key sites of the p38α mitogen activated protein kinase (MAPK) exploited for the design of inhibitors. This study demonstrated design of peptide inhibitor on the basis of allosteric site using Glide molecular docking software and the biochemical analysis of the best modeled peptide. The best fitted tetrapeptide (FWCS) in the allosteric site inhibited the pure recombinant and serum p38α of HNSCC patients by 74 and 72%, respectively. The potency of the peptide was demonstrated by its IC50 (4.6 nM) and KD (3.41×10-10 M) values, determined by ELISA and by surface plasmon resonance (SPR) technology, respectively. The cell viability of oral cancer i.e. KB cell line was reduced in dose dependent manner by 60 and 97% by the treatment of peptide and the IC50 was 600 and 210 µM after 24 and 72 h incubation, respectively. Our result provides an insight for the development of a proficient small peptide as a promising anticancer agent targeting DFG site of p38α kinase.

In silico assessment of S100A12 monomer and dimer structural dynamics: implications for the understanding of its metal-induced conformational changes

Changes in the concentration of different ions modulate several cellular processes, such as Ca(2+) and Zn(2+) in inflammation. Upon activation of immune system effector cells, the intracellular Ca(2+) concentration rises propagating the activation signal, leading to degranulation and generation of reactive oxygen species, which increases the Zn(2+) intracellular concentration as a consequence of the cellular antioxidant machinery. In this context, S100A12 is of special interest because it is a pro-inflammatory protein expressed in neutrophils whose structure and function are modulated by both Ca(2+) and Zn(2+). The current hypothesis about its mechanism of action was built based on biochemical and crystallographic data. However, there are missing connections between molecular structure and the way in which many events are concatenated at the triggering and along the inflammatory process. In this work we use molecular dynamics simulations to describe how variations in Zn(2+) and Ca(2+) concentrations modulate the structural dynamics of the calcium-free S100A12 dimer and monomer, which was not considered a part of the mechanism of action before. Our results suggest that (i) Zn(2+) have a determinant role in the dimerization step, as well as in the unbinding of the Na(+) complexed to the N-terminal EF-hand; (ii) the N-terminal EF-hand domain is the first to bind Ca(2+), and not the C-terminal, as usually accepted; and that (iii) Ca(2+) modulates the structural dynamics of H-III.

Annexin A11 gene polymorphism (R230C variant) and sarcoidosis in a Portuguese population

A recent genome-wide association study detected a protective effect for the annexin A11 rs1049550*T allele (R230Cvariant) in susceptibility to sarcoidosis. We evaluated the association between rs1049550 C/T and sarcoidosis susceptibility, distinct disease phenotypes and evolution in a Portuguese population. We performed a case-control study of 208 patients and 197 healthy controls. Samples were genotyped for rs1049550 C/T using real-time polymerase chain reaction. The frequency of the annexin A11 rs1049550*T allele was significantly lower in patients than in controls (33.2 vs 44.9%, P < 0.001). Odds ratio of 0.52 and 0.44 were obtained, respectively for carriers of one (CT) and two (TT) copies normalized to the CC wild-type genotype (P < 0.001). There were no significant differences in patients with and without Löfgren syndrome. A significant increase in the frequency of the T allele was observed in patients with bronchoalveolar lavage (BAL) fluid neutrophilia (P = 0.04). No significant associations were seen for lung function pattern, radiological stages or different forms of disease evolution. Our study confirms that rs1049550*T allele exerts a significant protective effect on sarcoidosis susceptibility. Given the role of annexin A11 in cell division, apoptosis and neutrophil function, this polymorphism may affect key elements of granulomatous and interstitial inflammation in sarcoidosis.

Annexin A11 in disease

Ubiquitously expressed in many cell types, annexin A11 (Anxa11) is a member of the multigene family of Ca(2+)-regulated phospholipid-dependent and membrane-binding annexin proteins. Studies have shown that Anxa11 plays an important role in cell division, Ca(2+) signaling, vesicle trafficking and apoptosis. The deregulation and mutation of Anxa11 are involved in systemic autoimmune diseases, sarcoidosis and the development, chemoresistance and recurrence of cancers. Malfunction of Anxa11 may lead to or enhance the metastasis, invasion and drug resistance of cancers through the platelet-derived growth factor receptor (PDGFR) pathway and/or the mitogen-activated protein kinase (MAPK)/p53 pathway. In a variety of diseases, Anxa11 is most commonly reported to function through interactions with apoptosis-linked gene-2 protein (ALG-2) and/or calcyclin (S100A6). Although it has been little studied, Anxa11 is a promising biomarker for the diagnosis, treatment and prognosis of certain diseases. In this review, the associations of Anxa11 with Ca(2+)-regulated exocytosis, cytokinesis, sex differentiation, autoimmune diseases, thrombolysis and cancers are summarized and interpreted.

Serum calprotectin as a biomarker for Crohn's disease

BACKGROUND AND AIMS

In Crohn's disease, correlation between clinical assessment and disease activity at tissue level is weak. Our aim was to evaluate the value of serum calprotectin as a biomarker for Crohn's disease.

METHODS

The STORI trial patients (n=115) were studied at baseline, in clinical remission before infliximab withdrawal, or at the time of relapse after infliximab withdrawal. Forty healthy controls were also studied. Serum calprotectin level was measured by ELISA. Data were analyzed through correlation analyses, Kaplan Meier curves and Cox model, using available Crohn's Disease Activity Index (CDAI), Crohn's Disease Endoscopic Index of Severity (CDEIS), fecal calprotectin and C-reactive protein levels (hsCRP).

RESULTS

Median serum calprotectin was 8892 ng/mL (range: 410-125,000 ng/mL) in Crohn disease patients as compared with 1318 ng/mL (range: 215.8-3770 ng/mL) in controls (P<0.0001). Serum calprotectin was significantly higher for active disease (median=19,584 ng/mL) than for inactive disease (median=8353 ng/mL) (P<0.0001). Serum calprotectin correlated with hsCRP (r=0.4092, P<0.0001) and CDAI (r=0.4442, P<0.0001), but not with CDEIS, on the contrary to fecal calprotectin (r=0.6458, 0.5515, 0.2577 with P<0.0001, P<0.0001, P=0.019 respectively). In multivariate analysis, serum calprotectin used as a discrete variable (threshold: 5675 ng/ml), appeared complementary to hsCRP (>5 mg/l) and fecal calprotectin (>250 μg/g) to predict relapse after infliximab withdrawal (P=0.0173, 0.0024 and 0.0002; HR: 3.191, 3.561 and 4.120).

CONCLUSIONS

As a CD biomarker, serum calprotectin has a similar profile as hsCRP. It is also complementary to fecal calprotectin and hsCRP for prediction of relapse after infliximab withdrawal.

Development of peptide inhibitor as a therapeutic agent against head and neck squamous cell carcinoma (HNSCC) targeting p38alpha MAP kinase

BACKGROUND

The p38alpha MAP kinase pathway is involved in inflammation, cell differentiation, growth, apoptosis and production of pro-inflammatory cytokines TNF-alpha and IL-1beta. The overproduction of these cytokines plays an important role in cancer. The aim of this work was to design a peptide inhibitor on the basis of structural information of the active site of p38alpha.

METHODS

A tetrapeptide, VWCS as p38alpha inhibitor was designed on the basis of structural information of the ATP binding site by molecular modeling. The inhibition study of peptide with p38alpha was performed by ELISA, binding study by Surface Plasmon Resonance and anti-proliferative assays by MTT and flow cytometry.

RESULTS

The percentage inhibition of designed VWCS against pure p38alpha protein and serum of HNSCC patients was 70.30 and 71.5%, respectively. The biochemical assay demonstrated the K(D) and IC50 of the selective peptide as 7.22 x 10(-9) M and 20.08 nM, respectively. The VWCS as inhibitor significantly reduced viability of oral cancer KB cell line with an IC50 value of 10 microM and induced apoptosis by activating Caspase 3 and 7.

CONCLUSIONS

VWCS efficiently interacted at the ATP binding pocket of p38alpha with high potency and can be used as a potent inhibitor in case of HNSCC.

GENERAL SIGNIFICANCE

VWCS can act as an anticancer agent as it potentially inhibits the cell growth and induces apoptosis in oral cancer cell-line in a dose as well as time dependent manner. Hence, p38alpha MAP kinase inhibitor can be a potential therapeutic agent for human oral cancer.

p38β MAP kinase as a therapeutic target for pancreatic cancer

Pancreatic cancer is very difficult to diagnose in its early stage. Molecular marker and imaging have not proven to be accurate modalities for screening of pancreatic cancer. This study aims to develop p38β as a protein marker for pancreatic cancer and to design peptide inhibitor against the same. The serum p38β level of pancreatic cancer (n = 35; 5.06 μg/mL) was twofold higher compared to that of the chronic pancreatitis (n = 10; 2.92 μg/mL) and matched normal control (n = 10; 2.86 μg/ml) (p < 0.0005). Peptide inhibitors were designed to inhibit the activity of p38β and the kinetic assay had shown the dissociation constant, (K(D)) to be 3.16 × 10(-8) M and IC(50), 25 nM by Surface Plasmon Resonance (SPR) and Enzyme-Linked Immunosorbent Assay (ELISA), respectively. The peptide inhibitor also significantly reduced viability and induced cytotoxicity in Human Pancreatic carcinoma epithelial-like cell line (PANC-1) cells.

Role of S100A12 in the pathogenesis of osteoarthritis

S100A12 is a member of the S100 protein family, which are intracellular calcium-binding proteins. Although there are many reports on the involvement of S100A12 in inflammatory diseases, its presence in osteoarthritic cartilage has not been reported. The purpose of this study was to investigate the expression of S100A12 in human articular cartilage in osteoarthritis (OA) and to evaluate the role of S100A12 in human OA chondrocytes. We analyzed S100A12 expression by immunohistochemical staining of cartilage samples obtained from OA and non-OA patients. In addition, chondrocytes were isolated from knee cartilage of OA patients and treated with recombinant human S100A12. Real-time RT-PCR was performed to analyze mRNA expression. Protein production of matrix metalloproteinase 13 (MMP-13) and vascular endothelial growth factor (VEGF) in the culture medium were measured by ELISA. Immunohistochemical analyses revealed that S100A12 expression was markedly increased in OA cartilages. Protein production and mRNA expression of MMP-13 and VEGF in cultured OA chondrocytes were significantly increased by treatment with exogenous S100A12. These increases in mRNA expression and protein production were suppressed by administration of soluble receptor for advanced glycation end products (RAGE). Both p38 mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) inhibitors also suppressed the increases in mRNA expression and protein production of MMP-13 and VEGF. We demonstrated marked up-regulation of S100A12 expression in human OA cartilages. Exogenous S100A12 increased the production of MMP-13 and VEGF in human OA chondrocytes. Our data indicate the possible involvement of S100A12 in the development of OA by up-regulating MMP-13 and VEGF via p38 MAPK and NF-κB pathways.

Immunohistochemical Characterization of S100A6 in the Murine Ovary

S100 proteins comprise a large family of Ca(2+)-binding proteins and exhibit a variety of intra- and extracellular functions. Despite our growing knowledge about the biology of S100 proteins in some tissues such as brain and smooth muscle, little is known about S100 proteins in the normal mammalian reproductive tissue. In the present study, we investigated the distribution pattern of S100A6 (alternatively named calcyclin) in the murine ovary by immunohistochemical study using specific antibody. S100A6 was localized substantially in the cytoplasm of luteal cells, with concomitant expression of S100A11, another S100 protein, but not in the other type of cells such as oocytes, follicle epithelial cells (granulosa cells), and cells of stroma including theca interna cells in the murine ovary. S100A6-immunoreactive corpora lutea (CLs) were divided into two types: homogeneously and heterogeneously stained CLs, and possibly they may represent differentiating and mature CL, respectively. Our regression analysis revealed that expression level of S100A6 positively correlated with that of cytochrome P450 11A, a steroidogenic enzyme in the heterogeously stained CL. These results suggested that S100A6 may contribute to differentiation of steroidogenic activity of luteal cells in a synergistic manner with S100A11 by facilitating some shared functions.

Expression of Pro-inflammatory Protein S100A12 (EN-RAGE) in Behçet's Disease and Its Association with Disease Activity: A Pilot Study

Background

S100A12 is a member of the S100 family of calcium-binding proteins and is secreted either in inflamed tissues or in the bloodstream by activated neutrophils. Expression of S100A12 has been reported in various diseases, especially non-infectious inflammatory diseases, such as Kawasaki disease, giant cell arteritis and inflammatory bowel disease.

Objective

This study was conducted to determine both the tissue expression and the serum levels of S100A12 in Behçet's disease (BD) patients and the correlation of the S100A12 serum level with disease activity of BD.

Methods

We included in this study ten BD patients who fulfilled the criteria for diagnosis, according to the International Study Group for BD. The activity of BD was calculated using the BD Current Activity Form. The serum concentrations of both S100A12 and interleukin-8 were measured by the enzyme-linked immunosorbent assay, before and after treatment. Immunohistochemical studies were also performed to detect S100A12 expression in the skin.

Results

The serum S100A12 level was significantly increased in the active BD period (p<0.001), in the inactive BD period (p=0.041) and in patients with active Kawasaki disease (p=0.028), compared with the serum level in the healthy controls. The serum S100A12 level decreased significantly from baseline, compared to post-treatment (p=0.017). The activity score of BD was significantly correlated with the serum level of S100A12 (Spearman's coefficient=0.464, p=0.039). Immunohistochemical studies showed that S100A12 was strongly expressed in the erythema nodosum-like skin lesions of patients.

Conclusion

S100A12 contributes to the pathogenesis of BD related to neutrophil hyperactivity and reflects the disease activity in BD patients.

Local calprotectin production in colorectal cancer and polyps--active neutrophil recruitment in carcinogenesis

AIM

The aim of this study is to examine the expression level and localization of calprotectin in cancer tissue, tumor-adjacent mucosa, and polyps in colonic biopsies. Calprotection expression was correlated with neutrophil infiltration, markers of bacteremia, and systemic inflammation.

MATERIALS AND METHODS

Patients with colorectal cancer (n = 28) and adenoma (n = 38) were compared with healthy controls (n = 33). Calprotectin expression levels were measured by ELISA, and its localization was visualized by immunohistochemistry and correlated with the degree of neutrophil infiltration (visualized by Esterase staining). The expression of tumor necrosis factor (TNF)-alpha, procalcitonin, endotoxemia, carcinoembryonic antigen (CEA), and C-reactive protein was also investigated.

RESULTS

Mucosal calprotectin was expressed in significantly higher concentrations in carcinoma (94.2 ± 31.2 ng/mg total protein) and adenoma (122.8 ± 60.3 ng/mg total protein) in comparison with mucosal biopsies from healthy controls (20.4 ± 5.4 ng/mg total protein), tumor-adjacent mucosa from patients with colorectal carcinoma (21.6 ± 5.1 ng/mg total protein), and adenoma (45 ± 14.6 ng/mg total protein, all p < 0.05). Immunohistochemistry showed calprotectin reactivity mainly in granulocytes and macrophages with only singular reactive epithelial cells. Positive staining (quantified by the number of positive cells per square millimeter) was markedly increased in carcinoma tissue (85 ± 21.5) and in adenoma (67.5 ± 20) as compared with tumor-adjacent epithelia (18.8 ± 4.3, p = 0.0007, p = 0.003, respectively), and there was a highly significant correlation, r = 0.89, p = 0.001) between calprotectin staining and neutrophil infiltration. No significant differences were found in the systemic levels of TNF-alpha, procalcitonin, and endotoxemia, whereas CEA and C-reactive protein levels were significantly higher in the cancer group (p < 0.05).

CONCLUSION

Our results support the evidence that increased calprotectin expression is an early step in the neoplastic transformation during colorectal carcinogenesis. Moreover, its expression is closely related to an inflammatory response and points out a possible biological link between inflammation and neoplastic transformation in colorectal cancer.

Faecal calprotectin in term and preterm neonates

OBJECTIVES

The aim of this review was to examine the characteristics of the faecal calprotectin assay in neonates and the evidence for its use as a noninvasive marker of intestinal illnesses during the neonatal period.

METHODS

Bibliographic searches were performed in the MEDLINE electronic database up to February 2010 looking for the following words (all fields): "infants" or "neonates" and "calprotectin." Twenty studies, in which 1180 neonates were enrolled, were selected.

RESULTS

During the neonatal period, calprotectin levels are characterized by significantly higher values in both healthy full-term and preterm infants during their first year of life compared with reference values established for children and adults. No difference was observed according to gestational age or birth weight, whereas a higher faecal calprotectin level was detected during intestinal distress in neonates with either inflammatory or patent digestive alterations. Despite high interindividual variations, cutoff levels are proposed to identify infants with a high risk of intestinal illnesses.

CONCLUSIONS

Compared with adults and children, healthy full-term and preterm neonates have high calprotectin levels. The measurement of calprotectin levels in faeces can be a promising noninvasive clinical screening test for intestinal distress in neonates.

Increased cerebrospinal fluid chitotriosidase index in patients with multiple sclerosis

OBJECTIVE

To investigate chitotriosidase (CTTS) activity in serum and cerebrospinal fluid (CSF) in multiple sclerosis (MS) patients in relation to disease course and CSF markers for immune activation or inflammation.

MATERIALS AND METHODS

We studied 80 patients with relapsing-remitting MS (RRMS), 24 with secondary progressive MS (SPMS), 20 with primary progressive MS (PPMS) and 29 patients with other neurological disorders (OND). We measured CTTS activity and studied the correlation with CSF mononuclear cell count (MNC) and intrathecal IgG production.

RESULTS

CTTS activity was significantly higher in CSF, but not in serum, from the total MS group compared with OND and controls. In RRMS and SPMS CTTS, index was increased compared with controls (RRMS, 0.10 +/- 0.21; SPMS, 0.10 +/- 0.15; controls, 0.021 +/- 0.020), but not in PPMS (0.061 +/- 0.052). CTTS index was higher in MS patients with elevated MNC or CSF-restricted oligoclonal IgG bands than in MS patients without these CSF findings.

CONCLUSIONS

CTTS index is elevated in RRMS and SPMS. The CTTS index is related to CSF markers of inflammation or immune activation.

Preliminary proteomic analysis of circulating polymorphonuclear neutrophils from rabbits experiencing scald injury and Staphylococcus aureus sepsis

BACKGROUND

The aim of this study is to identify the differentially expressed proteins in circulating polymorphonuclear neutrophils (PMN) from scalded bacteremia rabbits infected with Staphylococcus aureus to provide a basis to reveal the pathogenesis of burns and sepsis.

METHODS

Rabbits were subjected to sham burn (A), A + bacterial challenge (B), 30% scald injury (C), or C + bacterial challenge (D). Bacterial challenge was inflicted as an injection of 2.0 x 10(8) cfu S. aureus 18 h after burn procedure. Animals were sacrificed 24 h after burn. PMN were isolated, and the differential proteins in the PMN from these animals were identified by two-dimensional electrophoresis coupled with MALDI-TOF-MS; two proteins were confirmed by Western blotting.

RESULTS

Twenty-one differential protein spots were found, and seven differential proteins were identified. Among the identified proteins, the expression levels of protein disulfide-isomerase and thiol-specific antioxidant protein were down-regulated in groups C and D, and two protein spots of annexin I were identified, one of which was down-regulated and another up-regulated in groups C and D.

CONCLUSIONS

Preliminary proteome changes in PMN from rabbits experiencing scald injury and S. aureus sepsis were revealed, which possibly play an important role in the inflammation and pathogenesis of sepsis after scald injury.

Blood-related proteomics

Blood-related proteomics is an emerging field, recently gaining momentum. Indeed, a wealth of data is now available and a plethora of groups has contributed to add pieces to the jigsaw puzzle of protein complexity within plasma and blood cells. In this review article we purported to sail across the mare magnum of the actual knowledge in this research endeavour. The main strides in proteomic investigations on red blood cells, platelets, plasma and white blood cells are hereby presented in a chronological order. Moreover, a glance is given at prospective studies which promise to shift the focus of attention from the end product to its provider, the donor, in a sort of Kantian "Copernican revolution". A well-rounded portrait of the usefulness of proteomics in blood-related research is accurately given. In particular, proteomic tools could be adopted to follow the main steps of the blood-banking production processes (a comparison of collection methods, pathogen inactivation techniques, storage protocols). Thus proteomics has been recently transformed from a mere basic-research extremely-expensive toy into a dramatically-sensitive and efficient eye-lens to either delve into the depths of the molecular mechanisms of blood and blood components or to establish quality parameters in the blood-banking production chain totally anew.

Hypoxia mediated release of endothelial microparticles and increased association of S100A12 with circulating neutrophils

Microparticles are released from the endothelium under normal homeostatic conditions and have been shown elevated in disease states, most notably those characterised by endothelial dysfunction. The endothelium is sensitive to oxidative stress/status and vascular cell adhesion molecule-1 (VCAM-1) expression is upregulated upon activated endothelium, furthermore the presence of VCAM-1 on microparticles is known. S100A12, a calcium binding protein part of the S100 family, is shown to be present on circulating leukocytes and is thought a sensitive marker to local inflammatory process, which may be driven by oxidative stress. Eight healthy males were subjected to breathing hypoxic air (15% O(2), approximately equivalent to 3000 metres altitude) for 80 minutes in a temperature controlled laboratory and venous blood samples were processed immediately for VCAM-1 microparticles (VCAM-1 MP) and S100A12 association with leukocytes by flow cytometry. A pre-hypoxic blood sample was used for comparison. Both VCAM-1 MP and S100A12 association with neutrophils were significantly elevated post hypoxic breathing later declining to levels observed in the pre-test samples. A similar trend was observed in both cases and a correlation may exist between these two markers in response to hypoxia. These data offer evidence using novel markers of endothelial and circulating blood responses to hypoxia.

Binding of S100 proteins to RAGE: an update

The Receptor for Advanced Glycation Endproducts (RAGE) is a multi-ligand receptor of the immunoglobulin family. RAGE interacts with structurally different ligands probably through the oligomerization of the receptor on the cell surface. However, the exact mechanism is unknown. Among RAGE ligands are members of the S100 protein family. S100 proteins are small calcium binding proteins with high structural homology. Several members of the family have been shown to interact with RAGE in vitro or in cell-based assays. Interestingly, many RAGE ligands appear to interact with distinct domains of the extracellular portion of RAGE and to trigger various cellular effects. In this review, we summarize the modes of S100 protein-RAGE interaction with regard to their cellular functions.

Development of novel peptide inhibitor of Lipoxygenase based on biochemical and BIAcore evidences

Lipoxygenase (LOX) are enzymes implicated in a broad range of inflammatory diseases, cancer, asthma and atherosclerosis. These diverse biological properties lead to the interesting target for the inhibition of this metabolic pathway of LOX. The drugs available in the market against LOX reported to have various side effects. To develop potent and selective therapeutic agents against LOX, it is essential to have the knowledge of its active site. Due to the lack of structural data of human LOX, researchers are using soybean LOX (sLOX) because of their availability and similarities in the active site structure. Based on the crystal structure of sLOX-3 and its complex with known inhibitors, we have designed a tripeptide, FWY which strongly inhibits sLOX-3 activity. The inhibition by peptide has been tested with purified sLOX-3 and with LOX present in blood serum of breast cancer patients in the presence of substrate linoleic acid and arachidonic acid respectively. The dissociation constant (K(D)) of the peptide with sLOX-3 as determined by Surface Plasmon Resonance (SPR) was 3.59x10(-9) M. The kinetic constant (K(i)) and IC(50), as determined biochemical methods were 7.41x10(-8) M and 0.15x10(-6) M respectively.

New Insights into the Biological and Clinical Significance of Fecal Calprotectin in Inflammatory Bowel Disease

Nowadays, calprotectin, a cytoplasmatic protein, released by activated neutrophilic polymorphonuclear cells (PMN) and/or monocytes-macrophages (MØ), is considered a good indicator of inflammation in several diseases. Accordingly, fecal calprotectin represents a good predictor of clinical relapse in ulcerative colitis (UC) patients, whereas conflicting results have been reported in Crohn's disease (CD) patients. In our study, in 76 IBD patients (29 CD and 47 UC) fecal calprotectin has been evaluated by a commercial ELISA kit. Results demonstrate that levels of this protein in the stool are significantly more elevated in active CD and UC patients than in normal volunteers. In quiescent CD and UC a trend to higher levels of calprotectin than in the normal counterpart is, however, evident. These data suggest that a low-grade inflammation of the intestinal wall is always present in CD and UC patients, which may predict a clinical relapse risk. In the same group of patients calprotectin levels also were analyzed according to sex and age. A trend to higher values of calprotectin was present in male patients with active or quiescent CD than in their female counterparts. Only in UC patients in remission a trend to calprotectin increase was more marked in the male group than in the female counterpart. When CD and UC patients were divided up according to age, calprotectin positivity peaked between 30-39 years in active CD patients, while in quiescent CD maximum positivity was between 40 and 49 years. However, in both active and quiescent UC patients, calprotectin positivity increased with age. The more precocious detectability of fecal calprotectin in CD patients, as a marker of intestinal mucosa inflammation, may be related to the different histopathology of the two diseases (CD versus UC). However, reduced PMN and/or MØ trafficking from peripheral blood to intestinal mucosa with age by effects of chronic treatment should not be ignored in CD patients.

The application of proteomics technology to thrombosis research: the identification of potential therapeutic targets in cardiovascular disease

Thrombus formation underpins the development of cardiovascular diseases, including acute coronary syndromes and ischaemic stroke. A number of well-characterised cardiovascular risk factors which contribute to the development of the majority of cardiovascular events have been identified, including dyslipidaemia, hypertension and diabetes. Individuals with type 2 diabetes mellitus (T2DM) have a 3- to 5-fold increased risk for development of cardiovascular disease (CVD). They may have a cluster of haemostatic abnormalities, including elevated levels of plasminogen activator inhibitor-1 (PAI-1) and fibrinogen, which contribute to acute thrombotic events. It is clear that additional unidentified risk factors contribute to the pathogenesis of cardiovascular events, and so the search for novel biomarkers and effectors, particularly in individuals with T2DM, remains a major challenge of cardiovascular medicine. Plasma and cellular proteins which contribute to thrombus formation have the potential to confer a pro-thrombotic state and represent a link between genotype, environment and disease phenotype. The comprehensive analysis of these proteins is now increasingly facilitated through the continued development of proteomic technologies which provide multifaceted approaches to the identification of novel biomarkers and/or effectors of thrombus formation and on which future anticoagulant and thrombolytic therapies may be based. This review provides an overview of current proteomic technologies. It focuses on the recent studies in which these technologies have been applied in the search for novel proteins that may confer increased risk of acute cardiovascular diseases and therefore that may influence disease progression and therapy.

Calprotectin is released from human skeletal muscle tissue during exercise

Skeletal muscle has been identified as a secretory organ. We hypothesized that IL-6, a cytokine secreted from skeletal muscle during exercise, could induce production of other secreted factors in skeletal muscle. IL-6 was infused for 3 h into healthy young males (n = 7) and muscle biopsies obtained at time points 0, 3 and 6 h in these individuals and in resting controls. Affymetrix microarray analysis of gene expression changes in skeletal muscle biopsies identified a small set of genes changed by IL-6 infusion. RT-PCR validation confirmed that S100A8 and S100A9 mRNA were up-regulated 3-fold in skeletal muscle following IL-6 infusion compared to controls. Furthermore, S100A8 and S100A9 mRNA levels were up-regulated 5-fold in human skeletal muscle following cycle ergometer exercise for 3 h at approximately 60% of in young healthy males (n = 8). S100A8 and S100A9 form calprotectin, which is known as an acute phase reactant. Plasma calprotectin increased 5-fold following acute cycle ergometer exercise in humans, but not following IL-6 infusion. To identify the source of calprotectin, healthy males (n = 7) performed two-legged dynamic knee extensor exercise for 3 h with a work load of approximately 50% of peak power output and arterial-femoral venous differences were obtained. Arterial plasma concentrations for calprotectin increased 2-fold compared to rest and there was a net release of calprotectin from the working muscle. In conclusion, IL-6 infusion and muscle contractions induce expression of S100A8 and S100A9 in skeletal muscle. However, IL-6 alone is not a sufficient stimulus to facilitate release of calprotectin from skeletal muscle.