Association of circulating levels of MMP-8 with mortality from respiratory disease in patients with rheumatoid arthritis

An updated patent review of matrix metalloproteinase (MMP) inhibitors (2021-present)

INTRODUCTION

Matrix metalloproteinases (MMPs) are strongly interlinked with the progression and mechanisms of several life-threatening diseases including cancer. Thus, novel MMP inhibitors (MMPIs) as promising drug candidates can be effective in combating these diseases. However, no MMPIs are marketed to date due to poor pharmacokinetics and lower selectivity. Therefore, this review was performed to study the newer MMPIs patented after the COVID-19 period for an updated perspective on MMPIs.

AREAS COVERED

This review highlights patents related to MMPIs, and their therapeutic implications published between January 2021 and August 2023 available in the Google Patents, Patentscope, and Espacenet databases.

EXPERT OPINION

Despite various MMP-related patents disclosed up to 2020, newer patent applications in the post-COVID-19 period decreased a lot. Besides major MMPs, other isoforms (i.e. MMP-3 and MMP-7) have gained attention recently for drug development. This may open up newer dimensions targeting these MMPs for therapeutic advancements. The isoform selectivity and bioavailability are major concerns for effective MMPI development. Thus, adopting theoretical approaches and experimental methodologies can unveil the development of novel MMPIs with improved pharmacokinetic profiles. Nevertheless, the involvement of MMPs in cancer, and the mechanisms of such MMPs in other diseases should be extensively studied for novel MMPI development.

Adverse birth outcomes are associated with circulating matrix metalloproteinases among pregnant women in Puerto Rico

Matrix metalloproteinases (MMPs) are major extracellular matrix (ECM) remodeling proteinases and regulate uterine remodeling, which is a critical process for healthy pregnancies. The goal of this study was to investigate associations between maternal blood MMPs during pregnancy and birth outcomes among 898 pregnant women in the Puerto Rico PROTECT birth cohort. MMPs (MMP1, MMP2, and MMP9) were quantified using a customized Luminex assay in blood samples collected at two gestational study visits (around 18 and 26 weeks gestation). Linear and logistic regression models were used to regress continuous and binary birth outcomes, respectively, on MMPs at each study visit separately. Sensitivity analyses were conducted to test for effect modification by fetal sex on associations between MMPs and birth outcomes. We observed significant associations between MMP2 at visit 1 and newborn length that were in the opposite direction from the associations between MMP9 at visit 3 and newborn length. MMPs were associated with increased odds of preeclampsia and gestational diabetes mellitus, though case numbers were low. We also observed significant inverse associations with gestational age for MMP9 and MMP2 at visit 1 and visit 3, respectively, and these associations were observed only in mothers carrying male fetuses. Further, MMP2 was associated with heavier female fetuses, whereas MMP9 was associated with lighter female fetuses. We observed significant associations between birth outcomes and MMPs, and the majority of these associations differed by fetal sex. This study highlighted significant MMPs-birth outcomes associations that may provide a basis to explore the impact of MMPs on endometrium health and physiology.

Role of phagocyte extracellular traps during Mycobacterium tuberculosis infections and tuberculosis disease processes

Mycobacterium tuberculosis (M.tb) infections remain one of the most significant causes of mortality worldwide. The current situation shows an emergence of new antibiotic-resistant strains making it difficult to control the tuberculosis (TB) disease. A large part of its success as a pathogen is due to its ability to persist for years or even decades without causing evident clinical manifestations. M.tb is highly successful in evading the host-defense by manipulating host-signalling pathways. Although macrophages are generally viewed as the key cell type involved in harboring M.tb, growing evidence shows that neutrophils also play a fundamental role. Both cells are known to act in multiple ways when encountering an invading pathogen, including phagocytosis, release of cytokines and chemokines, and oxidative burst. In addition, the formation of neutrophil extracellular traps (NETs) and macrophage extracellular traps (METs) has been described to contribute to M.tb infections. NETs/METs are extracellular DNA fibers with associated granule components, which are released upon activation of the cells by the pathogen or by pro-inflammatory mediators. On one hand, they can lead to a protective immune response by entrapment and killing of pathogens. However, on the other hand, they can also play a severe pathological role by inducing tissue damage. Extracellular traps (ETs) produced in the pulmonary alveoli can expand easily and expose tissue-damaging factors with detrimental effects. Since host-directed therapies offer a complementary strategy in TB, the knowledge of NET/MET formation is important for understanding potential protective versus detrimental pathways during innate immune signaling. In this review, we summarize the progress made in understanding the role of NETs/METs in the pathogenesis of TB.

Neutrophils' Extracellular Trap Mechanisms: From Physiology to Pathology

Neutrophils are an essential part of the innate immune system and the first line of defense against invading pathogens. They phagocytose, release granular contents, produce reactive oxygen species, and form neutrophil extracellular traps (NETs) to fight pathogens. With the characterization of NETs and their components, neutrophils were identified as players of the innate adaptive crosstalk. This has placed NETs at the center not only of physiological but also pathological processes. Aside from their role in pathogen uptake and clearance, NETs have been demonstrated to contribute to the resolution of inflammation by forming aggregated NETs able to degrade inflammatory mediators. On the other hand, NETs have the potential to foster severe pathological conditions. When homeostasis is disrupted, they occlude vessels and ducts, serve as sources of autoantigens and danger or damage associated molecular patterns, directly damage tissues, and exaggerate complement activity and inflammation. This review focusses on the understanding of NETs from their formation to their functions in both physiological and pathological processes.

Syndrome of Combined Pulmonary Fibrosis and Emphysema: An Official ATS/ERS/JRS/ALAT Research Statement

Background: The presence of emphysema is relatively common in patients with fibrotic interstitial lung disease. This has been designated combined pulmonary fibrosis and emphysema (CPFE). The lack of consensus over definitions and diagnostic criteria has limited CPFE research. Goals: The objectives of this task force were to review the terminology, definition, characteristics, pathophysiology, and research priorities of CPFE and to explore whether CPFE is a syndrome. Methods: This research statement was developed by a committee including 19 pulmonologists, 5 radiologists, 3 pathologists, 2 methodologists, and 2 patient representatives. The final document was supported by a focused systematic review that identified and summarized all recent publications related to CPFE. Results: This task force identified that patients with CPFE are predominantly male, with a history of smoking, severe dyspnea, relatively preserved airflow rates and lung volumes on spirometry, severely impaired DlCO, exertional hypoxemia, frequent pulmonary hypertension, and a dismal prognosis. The committee proposes to identify CPFE as a syndrome, given the clustering of pulmonary fibrosis and emphysema, shared pathogenetic pathways, unique considerations related to disease progression, increased risk of complications (pulmonary hypertension, lung cancer, and/or mortality), and implications for clinical trial design. There are varying features of interstitial lung disease and emphysema in CPFE. The committee offers a research definition and classification criteria and proposes that studies on CPFE include a comprehensive description of radiologic and, when available, pathological patterns, including some recently described patterns such as smoking-related interstitial fibrosis. Conclusions: This statement delineates the syndrome of CPFE and highlights research priorities.

Glycolysis in Innate Immune Cells Contributes to Autoimmunity

Autoimmune diseases (AIDs) refer to connective tissue inflammation caused by aberrant autoantibodies resulting from dysfunctional immune surveillance. Most of the current treatments for AIDs use non-selective immunosuppressive agents. Although these therapies successfully control the disease process, patients experience significant side effects, particularly an increased risk of infection. There is a great need to study the pathogenesis of AIDs to facilitate the development of selective inhibitors for inflammatory signaling to overcome the limitations of traditional therapies. Immune cells alter their predominant metabolic profile from mitochondrial respiration to glycolysis in AIDs. This metabolic reprogramming, known to occur in adaptive immune cells, i.e., B and T lymphocytes, is critical to the pathogenesis of connective tissue inflammation. At the cellular level, this metabolic switch involves multiple signaling molecules, including serine–threonine protein kinase, mammalian target of rapamycin, and phosphoinositide 3-kinase. Although glycolysis is less efficient than mitochondrial respiration in terms of ATP production, immune cells can promote disease progression by enhancing glycolysis to satisfy cellular functions. Recent studies have shown that active glycolytic metabolism may also account for the cellular physiology of innate immune cells in AIDs. However, the mechanism by which glycolysis affects innate immunity and participates in the pathogenesis of AIDs remains to be elucidated. Therefore, we reviewed the molecular mechanisms, including key enzymes, signaling pathways, and inflammatory factors, that could explain the relationship between glycolysis and the pro-inflammatory phenotype of innate immune cells such as neutrophils, macrophages, and dendritic cells. Additionally, we summarize the impact of glycolysis on the pathophysiological processes of AIDs, including systemic lupus erythematosus, rheumatoid arthritis, vasculitis, and ankylosing spondylitis, and discuss potential therapeutic targets. The discovery that immune cell metabolism characterized by glycolysis may regulate inflammation broadens the avenues for treating AIDs by modulating immune cell metabolism.

Inhibition of NETosis for treatment purposes: friend or foe?

Active neutrophils participate in innate and adaptive immune responses through various mechanisms, one of the most important of which is the formation and release of neutrophil extracellular traps (NETs). The NETs are composed of network-like structures made of histone proteins, DNA and other released antibacterial proteins by activated neutrophils, and evidence suggests that in addition to the innate defense against infections, NETosis plays an important role in the pathogenesis of several other non-infectious pathological states, such as autoimmune diseases and even cancer. Therefore, targeting NET has become one of the important therapeutic approaches and has been considered by researchers. NET inhibitors or other molecules involved in the NET formation, such as the protein arginine deiminase 4 (PAD4) enzyme, an arginine-to-citrulline converter, participate in chromatin condensation and NET formation, is the basis of this therapeutic approach. The important point is whether complete inhibition of NETosis can be helpful because by inhibiting this mechanism, the activity of neutrophils is suppressed. In this review, the biology of NETosis and its role in the pathogenesis of some important diseases have been summarized, and the consequences of treatment based on inhibition of NET formation have been discussed.

Predictors of Cardiovascular Affection in Patients with Active Rheumatoid Arthritis: Secondary Analysis of a Randomized Controlled Trial

OBJECTIVE

This is a secondary analysis of a randomized controlled trial that aimed to assess subclinical atherosclerosis in patients with rheumatoid arthritis (RA) by measuring carotid artery intima-media thickness (CIMT) and correlating it with disease activity and inflammatory markers (including levels of matrix metalloproteinase-3(MMP-3) and matrix metalloproteinase-9 (MMP-9)) and to detect the effectiveness of agents that inhibit matrix metalloproteinases (MMPs) as doxycycline in RA therapy.

METHODS

One hundred and sixty RA patients were assigned in a randomized clinical trial (clinicaltrial. gov NCT03194204). Disease activity score 28(DAS28), laboratory markers, including erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), MMP-3, and MMP-9 were evaluated and mean CIMT was measured. Subjects were allocated randomly into one of two treatment arms, either methotrexate (MTX) alone or MTX with doxycycline 200mg per day orally. Follow up ESR, CRP, DAS28, MMP-3, and MMP-9 levels were re-evaluated after 3 months.

RESULTS

There were positive significant correlations between CIMT and disease duration (r = 0.461, p = 0.001), age (r=0.459, p= 0.001), DAS28 score (r= 0.547, p = 0.001), ESR (r =0.413, p = 0.001), CRP (r = 0.281, p = 0.001), MMP-3 (r = 0.476, p = 0.001), and MMP-9 (r = 0.593, p =0.001). Patients treated with MTX and doxycycline showed lower levels of DAS28, ESR, CRP, MMP-3, and MMP-9 and this was statistically significant.

CONCLUSION

CIMT seems to be the ultimate method to screen for subclinical atherosclerosis in RA patients. MMP-3 and 9 play a key role in both RA synovitis and cardiovascular changes, making them important therapeutic targets, especially with safe and cost-effective agents like doxycycline. This clinical trial was carried out in Assiut University Hospital (AUH), Assiut, Egypt (Clinical Trial Registration No. clinicaltrial.gov NCT03194204).

Neutrophils in the Pathogenesis of Rheumatoid Arthritis and Systemic Lupus Erythematosus: Same Foe Different M.O

Dysregulated neutrophil activation contributes to the pathogenesis of autoimmune diseases including rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). Neutrophil-derived reactive oxygen species (ROS) and granule proteases are implicated in damage to and destruction of host tissues in both conditions (cartilage in RA, vascular tissue in SLE) and also in the pathogenic post-translational modification of DNA and proteins. Neutrophil-derived cytokines and chemokines regulate both the innate and adaptive immune responses in RA and SLE, and neutrophil extracellular traps (NETs) expose nuclear neoepitopes (citrullinated proteins in RA, double-stranded DNA and nuclear proteins in SLE) to the immune system, initiating the production of auto-antibodies (ACPA in RA, anti-dsDNA and anti-acetylated/methylated histones in SLE). Neutrophil apoptosis is dysregulated in both conditions: in RA, delayed apoptosis within synovial joints contributes to chronic inflammation, immune cell recruitment and prolonged release of proteolytic enzymes, whereas in SLE enhanced apoptosis leads to increased apoptotic burden associated with development of anti-nuclear auto-antibodies. An unbalanced energy metabolism in SLE and RA neutrophils contributes to the pathology of both diseases; increased hypoxia and glycolysis in RA drives neutrophil activation and NET production, whereas decreased redox capacity increases ROS-mediated damage in SLE. Neutrophil low-density granulocytes (LDGs), present in high numbers in the blood of both RA and SLE patients, have opposing phenotypes contributing to clinical manifestations of each disease. In this review we will describe the complex and contrasting phenotype of neutrophils and LDGs in RA and SLE and discuss their discrete roles in the pathogenesis of each condition. We will also review our current understanding of transcriptomic and metabolomic regulation of neutrophil phenotype in RA and SLE and discuss opportunities for therapeutic targeting of neutrophil activation in inflammatory auto-immune disease.

Sex differences in the blood-brain barrier and neurodegenerative diseases

The number of people diagnosed with neurodegenerative diseases is on the rise. Many of these diseases, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and motor neuron disease, demonstrate clear sexual dimorphisms. While sex as a biological variable must now be included in animal studies, sex is rarely included in in vitro models of human neurodegenerative disease. In this Review, we describe these sex-related differences in neurodegenerative diseases and the blood-brain barrier (BBB), whose dysfunction is linked to neurodegenerative disease development and progression. We explain potential mechanisms by which sex and sex hormones affect BBB integrity. Finally, we summarize current in vitro BBB bioengineered models and highlight their potential to study sex differences in BBB integrity and neurodegenerative disease.

Zinc and Cadmium in the Aetiology and Pathogenesis of Osteoarthritis and Rheumatoid Arthritis

Osteoarthritis (OA) and rheumatoid arthritis (RA) are inflammatory articular conditions with different aetiology, but both result in joint damage. The nutritionally essential metal zinc (Zn²⁺) and the non-essential metal cadmium (Cd²⁺) have roles in these arthritic diseases as effectors of the immune system, inflammation, and metabolism. Despite both metal ions being redox-inert in biology, they affect the redox balance. It has been known for decades that zinc decreases in the blood of RA patients. It is largely unknown, however, whether this change is only a manifestation of an acute phase response in inflammation or relates to altered availability of zinc in tissues and consequently requires changes of zinc in the diet. As a cofactor in over 3000 human proteins and as a signaling ion, zinc affects many pathways relevant for arthritic disease. How it affects the diseases is not just a question of zinc status, but also an issue of mutations in the many proteins that maintain cellular zinc homoeostasis, such as zinc transporters of the ZIP (Zrt-/Irt-like protein) and ZnT families and metallothioneins, and the multiple pathways that change the expression of these proteins. Cadmium interferes with zinc's functions and there is increased uptake under zinc deficiency. Remarkably, cadmium exposure through inhalation is now recognized in the activation of macrophages to a pro-inflammatory state and suggested as a trigger of a specific form of nodular RA. Here, we discuss how these metal ions participate in the genetic, metabolic, and environmental factors that lead to joint destruction. We conclude that both metal ions should be monitored routinely in arthritic disease and that there is untapped potential for prognosis and treatment.

Neutrophil Extracellular Traps (NETs) Take the Central Stage in Driving Autoimmune Responses

Following fifteen years of research, neutrophil extracellular traps (NETs) are widely reported in a large range of inflammatory infectious and non-infectious diseases. Cumulating evidences from in vitro, in vivo and clinical diagnostics suggest that NETs may play a crucial role in inflammation and autoimmunity in a variety of autoimmune diseases, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV). Most likely, NETs contribute to breaking self-tolerance in autoimmune diseases in several ways. During this review, we discuss the current knowledge on how NETs could drive autoimmune responses. NETs can break self-tolerance by being a source of autoantigens for autoantibodies found in autoimmune diseases, such as anti-citrullinated protein antibodies (ACPAs) in RA, anti-dsDNA in SLE and anti-myeloperoxidase and anti-protein 3 in AAV. Moreover, NET components could accelerate the inflammatory response by mediating complement activation, acting as danger-associated molecular patterns (DAMPs) and inflammasome activators, for example. NETs also can activate other immune cells, such as B cells, antigen-presenting cells and T cells. Additionally, impaired clearance of NETs in autoimmune diseases prolongs the presence of active NETs and their components and, in this way, accelerate immune responses. NETs have not only been implicated as drivers of inflammation, but also are linked to resolution of inflammation. Therefore, NETs may be central regulators of inflammation and autoimmunity, serve as biomarkers, as well as promising targets for future therapeutics of inflammatory autoimmune diseases.

Soluble EMMPRIN levels discriminate aortic ectasia in Marfan syndrome patients

Marfan syndrome (MFS) is a rare genetic disease characterized by a matrix metalloproteases (MMPs) dysregulation that leads to extracellular matrix degradation. Consequently, MFS patients are prone to develop progressive thoracic aortic enlargement and detrimental aneurysm. Since MMPs are activated by the extracellular MMP inducer (EMMPRIN) protein, we determined whether its plasmatic soluble form (sEMMPRIN) may be considered a marker of thoracic aortic ectasia (AE). Methods: We compared plasma sEMMPRIN levels of 42 adult Caucasian MFS patients not previously subjected to aortic surgery with those of matched healthy controls (HC) by ELISA. In the MFS cohort we prospectively evaluated the relationship between plasma sEMMPRIN levels and the main MFS-related manifestations. Results: MFS patients had lower plasma sEMMPRIN levels (mean±SD: 2071±637 pg/ml) than HC (2441±642 pg/ml, p=0.009). Amongst all considered MFS-related clinical features, we found that only aortic root dilatation associated with circulating sEMMPRIN levels. Specifically, plasma sEMMPRIN levels negatively correlated with aortic Z-score (r=-0.431, p=0.004), and were significantly lower in patients with AE (Z-score≥2, 1788±510 pg/ml) compared to those without AE (Z-score<2, 2355±634 pg/ml; p=0.003). ROC curve analysis revealed that plasma sEMMPRIN levels discriminated patients with AE (AUC [95%CI]: 0.763 [0.610-0.916], p=0.003) with 85.7% sensitivity, 76.2% specificity, and 81% accuracy. We defined plasma sEMMPRIN levels ≤2246 pg/ml as the best threshold discriminating the presence of AE in MFS patients with an odds ratio [95%CI] of 19.2 [3.947-93.389] (p<0.001). Conclusions: MFS patients are characterized by lower sEMMPRIN levels than HC. Notably, plasma sEMMPRIN levels are strongly associated with thoracic AE.

Caught in a Trap? Proteomic Analysis of Neutrophil Extracellular Traps in Rheumatoid Arthritis and Systemic Lupus Erythematosus

Neutrophil Extracellular Traps (NETs) are implicated in the development of auto-immunity in diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) through the externalization of intracellular neoepitopes e.g., dsDNA and nuclear proteins in SLE and citrullinated peptides in RA. The aim of this work was to use quantitative proteomics to identify and measure NET proteins produced by neutrophils from healthy controls, and from patients with RA and SLE to determine if NETs can be differentially-generated to expose different sets of neoepitopes. Ultra-pure neutrophils (>99%) from healthy individuals (n = 3) and patients with RA or SLE (n = 6 each) were incubated ± PMA (50 nM, PKC super-activator) or A23187 (3.8 μM, calcium ionophore) for 4 h. NETs were liberated by nuclease digestion and concentrated onto Strataclean beads prior to on-bead digestion with trypsin. Data-dependent LC-MS/MS analyses were conducted on a QExactive HF quadrupole-Orbitrap mass spectrometer, and label-free protein quantification was carried out using Progenesis QI. PMA-induced NETs were decorated with annexins, azurocidin and histone H3, whereas A23187-induced NETs were decorated with granule proteins including CAMP/LL37, CRISP3, lipocalin and MMP8, histones H1.0, H1.4, and H1.5, interleukin-8, protein-arginine deiminase-4 (PADI4), and α-enolase. Four proteins were significantly different between PMA-NETs from RA and SLE neutrophils (p < 0.05): RNASE2 was higher in RA, whereas MPO, leukocyte elastase inhibitor and thymidine phosphorylase were higher in SLE. For A23187-NETs, six NET proteins were higher in RA (p < 0.05), including CAMP/LL37, CRISP3, interleukin-8, MMP8; Thirteen proteins were higher in SLE, including histones H1.0, H2B, and H4. This work provides the first, direct comparison of NOX2-dependent (PMA) and NOX2-independent (A23187) NETs using quantitative proteomics, and the first direct comparison of RA and SLE NETs using quantitative proteomics. We show that it is the nature of the stimulant rather than neutrophil physiology that determines NET protein profiles in disease, since stimulation of NETosis in either a NOX2-dependent or a NOX2-independent manner generates broadly similar NET proteins irrespective of the disease background. We also use our proteomics pipeline to identify an extensive range of post-translationally modified proteins in RA and SLE, including histones and granule proteins, many of which are known targets of auto-antibodies in each disease.

Inflammatory biomarkers in saliva and serum of patients with rheumatoid arthritis with respect to periodontal status

OBJECTIVE

To study prospectively the association of salivary and serum matrix metalloproteinase (MMP)-8, tissue inhibitor of MMPs (TIMP)-1 and interleukin (IL)-6 with periodontal and systemic inflammation in rheumatoid arthritis (RA). We hypothesized that biomarker concentrations reflect inflammation.

METHODS

Fifty three early untreated RA (ERA) and 28 chronic RA (CRA) patients, underwent rheumatological and dental examinations at baseline and one year later after starting first conventional or biological disease modifying antirheumatic drug. We included 43 control subjects. Saliva and serum samples were analyzed for MMP-8, TIMP-1 and IL-6. Periodontal health was assessed by bleeding on probing (BOP), pocket depth (PD) and periodontal inflammatory burden index (PIBI); RA disease activity was assessed by disease activity score DAS28. Joint destruction was analyzed by the modified Sharp-van der Heijde (SHS) method.

RESULTS

Serum MMP-8 (p < .001; p < .001) and IL-6 (p < .001; p = .002) were significantly higher in CRA vs. other study groups during the study. Salivary MMP-8 (p = .010) and IL-6 (p = .010) were significantly higher in ERA vs. other study groups at baseline. Salivary MMP-8 was associated with periodontal parameters.

CONCLUSION

Elevated serum concentrations of MMP-8 and IL-6 in CRA patients reflected chronic RA, while elevated salivary concentrations of MMP-8 levels in ERA patients reflected increased periodontal inflammation. Key messages Concentrations of inflammatory biomarkers in serum and saliva were different between patients with RA and healthy controls. Concentrations of MMP-8 and of IL-6 in serum were elevated in patients with chronic RA reflecting joint inflammation and the burden of established RA. Concentrations of MMP-8 in saliva was elevated already at the early stage of RA and the level of salivary MMP-8 was associated with poor periodontal health both in patients with early and in those with chronic RA.

MMP-8 and TIMP-1 are associated to periodontal inflammation in patients with rheumatoid arthritis under methotrexate immunosuppression - First results of a cross-sectional study

BACKGROUND

Aim of this cross-sectional study was the investigation of associations between different rheumatoid arthritis (RA)-related blood parameters and periodontal condition as well as selected periodontal pathogenic bacteria in RA patients under methotrexate (MTX) immunosuppression.

METHODS

Periodontal probing depth (PPD), bleeding on probing (BOP) and clinical attachment loss (CAL) were assessed. Periodontal condition was classified into: no/mild and moderate or severe periodontitis (P). Prevalence of selected periodontal pathogenic bacteria and concentration of matrix metalloproteinase 8 (MMP-8) was assessed from the gingival crevicular fluid (GCF) using PCR and ELISA, respectively. Blood samples were analyzed for the concentration of selected rheumatoid parameters.

STATISTICAL ANALYSIS

t-test, Mann-Whitney-U-Test, exact Fisher tests or chi square test (p < 0.05).

RESULTS

Fifty-six patients (mean age 55.07 years, 34 P, 22 no P) were included. While prevalence of periodontal pathogenic bacteria was higher in P patients, no substantial association of bacteria with blood parameters was found. In periodontal diseased participants, MMP-8 concentration in GCF (6.22 ± 7.01 vs. 15.99 ± 13.49; p < 0.01) and blood (2.60 ± 3.57 vs. 5.52 ± 5.92; p < 0.01) was increased, while no correlation between GCF and blood was found (Spearman's rho: 0.175; p = 0.23). Furthermore, higher blood concentrations of MMP-8 and tissue inhibitor of MMP (TIMP-1) were detected in patients with increased periodontal inflammation (BOP positive, p < 0.01).

CONCLUSION

Periodontal inflammation appears associated to MMP-8 and TIMP-1 in blood. Thereby, clinical interaction between periodontal conditions, periodontal pathogenic bacteria and RA-related cytokines remain unclear.

The effect of gender and genetic polymorphisms on matrix metalloprotease (MMP) and tissue inhibitor (TIMP) plasma levels in different infectious and non-infectious conditions

Matrix metalloproteases (MMPs) are increased in different infections due to their role in controlling immune responses and are regulated by tissue inhibitors (TIMPs). Different MMP promoter single nucleotide polymorphisms (SNPs) induce changes in MMP genes, mRNA and protein expression. Gender might also modify MMP plasma levels. In order to determine the weight of these variables on MMP secretion we studied MMP-1, -2, -3, -8, -9, -10, -13 and TIMP-1, -2, -4 plasma levels in 90 patients with severe bacterial sepsis, 102 with anti-retroviral (ARV)-treated HIV monoinfection, 111 with ARV-treated HIV-hepatitis C virus (HCV) co-infection and 86 non-infected controls (45 stroke and 41 trauma patients). MMP-1(-1607 1G/2G), MMP-3(-1612 5A/6A), MMP-8(-799C/T), MMP-9(-1562 C/T) and MMP-13(-77A/G) SNPs were genotyped. MMP-3 plasma levels were significantly higher in men than in women in each diagnostic group, and MMP-3 SNP allele 6A carriers also had higher levels than allele 5A carriers, an effect that was magnified by sepsis. Independent predictors of higher MMP-3 levels were male gender (P = 0.0001), MMP-3(-1612 5A/6A) SNP (P = 0.001), higher levels of TIMP-4 (P = 0.004) and MMP-8 (P = 0.006) and lower levels of MMP-1 (P = 0.03) by multivariate analysis. No strong associations with gender or SNPs were observed for other MMPs or TIMPs. In conclusion, male gender and MMP-3(-1612 5A/6A) 6A allele carriage increased MMP-3 plasma levels significantly, especially in patients with severe bacterial sepsis. This confounding gender effect needs to be addressed when evaluating MMP-3 plasma levels in any infectious or non-infectious condition.

Gender-dependent differences in plasma matrix metalloproteinase-8 elevated in pulmonary tuberculosis

Tuberculosis (TB) remains a global health pandemic and greater understanding of underlying pathogenesis is required to develop novel therapeutic and diagnostic approaches. Matrix metalloproteinases (MMPs) are emerging as key effectors of tissue destruction in TB but have not been comprehensively studied in plasma, nor have gender differences been investigated. We measured the plasma concentrations of MMPs in a carefully characterised, prospectively recruited clinical cohort of 380 individuals. The collagenases, MMP-1 and MMP-8, were elevated in plasma of patients with pulmonary TB relative to healthy controls, and MMP-7 (matrilysin) and MMP-9 (gelatinase B) were also increased. MMP-8 was TB-specific (p<0.001), not being elevated in symptomatic controls (symptoms suspicious of TB but active disease excluded). Plasma MMP-8 concentrations inversely correlated with body mass index. Plasma MMP-8 concentration was 1.51-fold higher in males than females with TB (p<0.05) and this difference was not due to greater disease severity in men. Gender-specific analysis of MMPs demonstrated consistent increase in MMP-1 and -8 in TB, but MMP-8 was a better discriminator for TB in men. Plasma collagenases are elevated in pulmonary TB and differ between men and women. Gender must be considered in investigation of TB immunopathology and development of novel diagnostic markers.

Biomarkers of cartilage and surrounding joint tissue

The identification and clinical demonstration of efficacy and safety of osteo- and chondro-protective drugs are met with certain difficulties. During the last few decades, the pharmaceutical industry has, in the field of rheumatology, experienced disappointments associated with the development of disease modification. Today, the vast amount of patients suffering from serious, chronic joint diseases can only be offered treatments aimed at improving symptoms, such as pain and acute inflammation, and are not aimed at protecting the joint tissue. This huge, unmet medical need has been the driver behind the development of improved analytical techniques allowing better and more efficient clinical trial design, implementation and analysis. With this review, we aim to provide a brief and general overview of biochemical markers of joint tissue, with special focus on neoepitopes. Furthermore, we highlight recent studies applying biochemical markers in joint degenerative diseases. These disorders, including osteoarthritis, rheumatoid arthritis and spondyloarthropathies, are the most predominant disorders in Europe and the USA, and have enormous socioeconomical impact.

Immunolocalization of MMP-2 and MMP-9 in human rheumatoid synovium

Matrix metalloproteinase (MMP)-2 and MMP-9, two important members of the matrix metalloproteinase family, have been shown critical contributions in intra-tumor angiogenesis and invasion of tumor progression, and they might also play important roles in the angiogenesis as well as the pannus formation of rheumatoid arthritis (RA). In the present study, we used the immunohistochemistry, the immunofluorescence staining and the con-focal scanning methods to characterize the immunolocalization of MMP-2 and MMP-9 in RA synovium tissues. Our results showed that both MMP-2 and MMP-9 immunostaining could be found in synoviocytes and vascular endothelial cells. Moreover, our con-focal scanning also showed that MMP-2 could be found in infiltrating CD14(+) monocytes and CD68(+) macrophages, and MMP-9 could be found in infiltrating CD68(+) macrophages in RA synovium tissues, while weak or negative staining of these two MMPs could be found in infiltrating CD20(+)B cells and CD3(+)T cells in RA synovium. Thus, our finding suggests that both MMP-2 and MMP-9 expressed by synoviocytes as well as certain infiltrating immune cells role importantly in the angiogenesis in RA progression.

Beneficial role of vitamin D3 in the prevention of certain respiratory diseases

There is evidence of aberrations in the vitamin D-endocrine system in subjects with respiratory diseases. Vitamin D deficiency is highly prevalent in patients with respiratory diseases, and patients who receive vitamin D have significantly larger improvements in inspiratory muscle strength and maximal oxygen uptake. Studies have provided an opportunity to determine which proteins link vitamin D to respiratory pathology, including the major histocompatibility complex class II molecules, vitamin D receptor, vitamin D-binding protein, chromosome P450, Toll-like receptors, poly(ADP-ribose) polymerase-1, and the reduced form of nicotinamide adenine dinucleotide phosphate. Vitamin D also exerts its effect on respiratory diseases through cell signaling mechanisms, including matrix metalloproteinases, mitogen-activated protein kinase pathways, the Wnt/β-catenin signaling pathway, prostaglandins, reactive oxygen species, and nitric oxide synthase. In conclusion, vitamin D plays a significant role in respiratory diseases. The best form of vitamin D for use in the treatment of respiratory diseases is calcitriol because it is the active metabolite of vitamin D3 and modulates inflammatory cytokine expression. Further investigation of calcitriol in respiratory diseases is needed.