Kirsten Junker

Serum amyloid P component inhibits influenza A virus infections: in vitro and in vivo studies

Serum amyloid P component (SAP) binds in vitro Ca(2+)-dependently to several ligands including oligosaccharides with terminal mannose and galactose. We have earlier reported that SAP binds to human influenza A virus strains, inhibiting hemagglutinin (HA) activity and virus infectivity in vitro. These studies were extended to comprise five mouse-adapted influenza A strains, two swine influenza A strains, a mink influenza A virus, a ferret influenza A reassortant virus, a influenza B virus and a parainfluenza 3 virus. The HA activity of all these viruses was inhibited by SAP. Western blotting showed that SAP bound to HA trimers, monomers and HA1 and HA2 subunits of influenza A virus. Binding studies indicated that galactose, mannose and fucose moieties contributed to the SAP reacting site(s). Intranasal administration of human SAP to mice induced no demonstrable toxic reactions, and circulating antibodies against SAP were not detected. Preincubation of virus (A/Japan/57) with SAP prevented primary infection of mice and development of antiviral antibodies. After a single intranasal administration of SAP (40 microg) 1 h before primary infection with virus (2LD(50)), nine out of 10 mice survived on day 10 and these mice approached normal body weight, whereas control mice (one out of five surviving on day 10) died. The data provide evidence of the potential of intranasally administered SAP for prophylactic treatment of influenza A virus infections in humans.

Circulating surfactant protein -D is low and correlates negatively with systemic inflammation in early, untreated rheumatoid arthritis

IntroductionSurfactant protein D (SP-D) is a collectin with immuno-regulatory functions, which may depend on oligomerization. Anti-microbial and anti-inflammatory properties have been attributed to multimeric SP-D variants, while trimeric subunits per se have been suggested to enhance inflammation. Previously, we reported low circulating SP-D in early rheumatoid arthritis (RA), and the present investigation aims to extend these data by serial SP-D serum measurements, studies on synovial fluid, SP-D size distribution and genotyping in patients with early RA.MethodsOne-hundred-and-sixty disease-modifying antirheumatic drug (DMARD) naïve RA patients with disease duration less than six months were studied prospectively for four years (CIMESTRA (Ciclosporine, Methotrexate, Steroid in RA) trial) including disease activity measures (C-reactive protein, joint counts and Health Assessment Questionnaire (HAQ) score), autoantibodies, x-ray findings and SP-D. SP-D was quantified by enzyme-linked immunosorbent assay (ELISA) and molecular size distribution was assessed by gel filtration chromatography. Further, SP-D Met11Thr single nucleotide polymorphism (SNP) analysis was performed.ResultsSerum SP-D was significantly lower in RA patients at baseline compared with healthy controls (P < 0.001). SP-D increased slightly during follow-up (P < 0.001), but was still subnormal at four years after adjustment for confounders (P < 0.001). SP-D in synovial fluid was up to 2.5-fold lower than in serum. While multimeric variants were detected in serum, SP-D in synovial fluid comprised trimeric subunits only. There were no significant associations between genotype distribution and SP-D. Baseline SP-D was inversely associated to CRP and HAQ score. A similar relationship was observed regarding temporal changes in SP-D and CRP (zero to four years). SP-D was not associated to x-ray findings.ConclusionsThis study confirms that circulating SP-D is persistently subnormal in early and untreated RA despite a favourable therapeutic response obtained during four years of follow-up. SP-D correlated negatively to disease activity measures, but was not correlated with x-ray progression or SP-D genotype. These observations suggest that SP-D is implicated in RA pathogenesis at the protein level. The exclusive presence of trimeric SP-D in affected joints may contribute to the maintenance of joint inflammation.Trial registration(j.nr NCT00209859).

Uncoupling of collagen II metabolism in newly diagnosed, untreated rheumatoid arthritis is linked to inflammation and antibodies against cyclic citrullinated peptides

Objective. To investigate the relationship between markers of collagen II synthesis and degradation with disease activity measures, autoantibodies, and radiographic outcomes in a 4-year protocol on patients with early rheumatoid arthritis (RA) who are naïve to disease-modifying antirheumatic drugs. Methods. One hundred sixty patients with newly diagnosed, untreated RA entered the Cyclosporine, Methotrexate, Steroid in RA (CIMESTRA) trial. Disease activity and radiograph status were measured at baseline and 4 years. The N-terminal propeptide of collagen IIA (PIIANP) and the cross-linked C-telopeptide of collagen II (CTX-II) were quantified at baseline by ELISA. PIIANP was also assayed at 2 and 4 years. Anticyclic citrullinated peptide (anti-CCP) was recorded at baseline. An uncoupling index for cartilage collagen metabolism was calculated from PIIANP and CTX-II measurements. Results. PIIANP was low at diagnosis and 4 years on (p < 0.001), irrespective of treatment and disease activity. PIIANP was lowest in anti-CCP positive patients (p = 0.006), and there was a negative correlation between PIIANP and anti-CCP titers (ρ = −0.25, p 0.002). CTX-II was increased (p < 0.001) and correlated positively with disease activity and radiographic progression, but not with anti-CCP (p = 0.93). The uncoupling index was not superior to CTX-II in predicting radiographic changes. Conclusion. These results suggest that cartilage collagen formation and degradation are unbalanced when RA is diagnosed. The different associations of collagen II anabolism (PIIANP) and collagen II degradation (CTX-II) with anti-CCP, synovitis, and radiographic progression indicate that at this early stage of RA, cartilage collagen degradation is mainly driven by synovitis, while anti-CCP antibodies may interfere with cartilage regeneration by inhibiting collagen IIA formation. Trial registration j.nr NCT00209859.

Surfactant protein D multimerization and gene polymorphism in COPD and asthma

A structural single nucleotide polymorphism rs721917 in the surfactant protein D (SP‐D) gene, known as Met11Thr, was reported to influence the circulating levels and degree of multimerization of SP‐D and was associated with both COPD and atopy in asthma. Moreover, disease‐related processes are known to degrade multimerized SP‐D, however, the degree of the protein degradation in these diseases is not clarified. We aimed to determine the distribution of multimerized (high molecular weight (HMW)) and non‐multimerized (low molecular weight (LMW)) species of serum SP‐D and their correlation with genetic polymorphisms and presence of disease in Lebanese COPD and asthmatic patients.

Within-day variation and influence of physical exercise on circulating Galectin-3 in patients with rheumatoid arthritis and healthy individuals

Galectin‐3 has been suggested as a pro‐inflammatory mediator in rheumatoid arthritis (RA). Previous studies have reported overexpression of Galectin‐3 in RA synovitis and increased levels in synovial fluid and serum in long‐standing RA compared with osteoarthritis and healthy controls. Our objectives were to study whether serum Galectin‐3 (1) exhibits circadian variation and/or (2) responds to exercise in RA and controls. The study on circadian patterns (1) comprised eleven patients with newly diagnosed RA, disease duration less than 6 months (ERA), 10 patients with long‐standing RA [5–15 years (LRA)] and 16 self‐reportedly healthy control subjects. During 24 h, 7 blood samples were drawn at 3‐h intervals starting at 10 a.m. through 10 p.m. and at 7 and 10 a.m. on the following day. The study on the effect of physical activity (2) included 10 patients with ERA, 10 with LRA and 14 controls. The participants underwent a standardized exercise programme and four blood samples were drawn before, during and after exercise. Serum Galectin‐3 was quantified by ELISA (R&D systems). (1) Galectin‐3 was increased at baseline in both RA subsets (P = 0.08). There were no diurnal oscillations (P = 0.85). Day‐to‐day variation amounted to 3%. (2) Baseline Galectin‐3 was increased in LRA versus controls and ERA (P < 0.01 and 0.05). Physical exercise induced 10–15% Galectin‐3 increments in RA and controls (P < 0.001) peaking after 1–3 h. To conclude, Galectin‐3 did not exhibit circadian variation. Day‐to‐day variation was 3%. Exercise elicited comparable increments in patients with RA of short and long duration and controls, approaching normal after 1–3 h.

Localization of surfactant protein-D in the rheumatoid synovial membrane

Surfactant protein‐D (SP‐D) is a collectin, which plays an important role in airway protection and inflammation. The molecule has both pro‐ and anti‐inflammatory capacities depending on its molecular size. Its involvement in joint diseases is largely unknown and the aim of this investigation was to study SP‐D occurrence and distribution in the synovial membrane of patients with long‐standing rheumatoid arthritis (RA) and osteoarthritis (OA). Six RA patients and six OA patients, who underwent total hip arthroplasty, were included in the study. Synovial tissue biopsies were obtained during surgery and subsequently prepared for immunohistochemistry. In this first, small‐scale comparative study on the occurrence of SP‐D in the synovial membrane of RA and OA, we report that SP‐D was only present in the microvascular endothelium in subsynovial and pannus tissue and that the immunostaining was much stronger than in OA. This distribution pattern suggests that SP‐D modulates RA inflammatory activities.

Galectin-3 is persistently increased in early rheumatoid arthritis (RA) and associates with anti-CCP seropositivity and MRI bony lesions, while early fibrosis markers correlate with disease activity

Galectin‐3 has been suggested as a pro‐inflammatory mediator in animal arthritis and rheumatoid arthritis (RA). We aimed to study the serum level of galectin‐3 in patients with newly diagnosed RA and associations with disease profile, Magnetic resonance imaging (MRI) findings and seromarkers of synovial matrix inflammation. One hundred and sixty DMARD naïve patients newly diagnosed with RA were included (CIMESTRA study). Clinical, serological and imaging data were recorded before treatment and at 6 weeks, 3 and 12 months. Galectin‐3 and hyaluronan (HYA) were measured by ELISA (R&D and Corgenix, USA), and the N‐terminal propeptide of type III collagen (PIIINP) by radioimmunoassay (Orion Diagnostica, Finland). One hundred and nineteen, 87 and 60 blood donors served as controls for galectin‐3, HYA and PIIINP, respectively. Baseline galectin‐3 was significantly elevated in anti‐CCP positive (4.2 μg/l IQR [3.6;6.1]) patients as compared with anti‐CCP negatives (4.0 μg/l [2.6;4.9], P = 0.05) and controls (3.8 μg/l [3.0;4.8], P < 0.01). During treatment, galectin‐3 remained elevated, but increased transiently with peak values at 6 weeks. Galectin‐3 correlated with baseline smoking, anti‐CCP, and with MRI erosion score after 1 year of follow‐up. HYA and PIIINP were elevated (P < 0.001) irrespective of anti‐CCP status and correlated positively with synovitis assessed clinically and by MRI. HYA and PIIINP did not correlate with galectin‐3. These observations indicate that HYA and PIIINP mainly reflect expansive synovitis proliferation while galectin‐3 is more closely linked to autoimmunity, smoking and joint destructive processes.

Circadian pattern and the effect of standardized physical exercise on procollagen IIA N-peptide (PIIANP) in rheumatoid arthritis at different stages and in healthy individuals

Background: Variant collagen IIA is re-expressed in diseased cartilage. Low procollagen IIA N-peptide (PIIANP) levels in serum have recently been reported in rheumatoid arthritis (RA). We investigated circadian rhythmicity and effect of physical activity on PIIANP in early and longstanding RA and in healthy subjects. Methods: Patients with early and longstanding RA and controls were included. Fasting and serial blood samples were collected during 24 h. PIIANP response to physical activity was studied before and serially after standardized exercise. Results and conclusion: In RA at different stages and healthy individuals, PIIANP exhibited no circadian rhythmicity, and PIIANP in serum was not influenced by physical activity.

Surfactant protein-D, a potential mediator of inflammation in axial spondyloarthritis

Objectives Surfactant protein-D (SP-D), an innate immune defence molecule of the collectin family, is expressed in lungs and additional extrapulmonary epithelia. SP-D has immune modulatory and anti-microbial effects depending on its oligomerization. The ratio of high molecular weight (HMW): low molecular weight (LMW) SP-D in serum is mainly determined by the Met11Thr polymorphism (SNP rs721917). We aimed to study the SP-D serum level and the molecular size distribution in patients with untreated axial spondyloarthritis (axSpA) as compared with control subjects. Methods Thirty-four patients with disease modifier untreated axSpA according to the ASAS criteria, age 19-63 years, disease duration 3.9 (2.2-5.6) years were included. Demographics, smoking habits, HLA-B27 status, ASDAS, BASDAI, BASFI, BASMI and visual analogue scale scores were recorded. SP-D in serum was measured by ELISA. DNA was isolated from whole blood and single nucleotide polymorphism rs721917 was genotyped. SP-D molecular size distribution was determined using gel filtration chromatography. Results SP-D in serum did not differ between patients with axSpA and healthy controls, 1177 (869, 1536) vs 910 (494, 1682) (P = 0.35) and SP-D did not correlate with disease activity. However, the HMW/LMW ratio of SP-D in serum was significantly lower in axSpA, 0.38 (0.18, 0.53) compared with controls 1.49 (0.37, 3.24) when adjusting for the Met11Thr polymorphism, gender, age, BMI and smoking (P = 0.0004). There was no correlation between HMW/LMW ratio and CRP or composite diseases outcome measures. Conclusion We suggest that predominance of LMW oligomeric variants of SP-D may enhance local or systemic inflammatory responses in axSpA.