A novel assay to quantitate MASP-2/ficolin-3 complexes in serum

Increased secreted frizzled-related protein 4 and ficolin-3 levels in gestational diabetes mellitus women

By biochemical and epidemiological similarity with type 2 diabetes mellitus (T2DM), gestational diabetes mellitus (GDM) has some overlap between prediction markers and risk factors of T2DM. The present study aimed to establish that secreted frizzled-related protein 4 (SFRP4) and ficolin-3 levels, which have been linked to insulin resistance and the development of T2DM, are elevated in GDM women. A longitudinal prospective cohort study of 86 GDM and 273 normal glucose tolerant (NGT) pregnant women was performed. The clinical parameters, lipid profiles, and serum SFRP4 and ficolin-3 levels were tested during the early and late second-trimester and third-trimester of pregnancy. Both SFRP4 and ficolin-3 levels were significantly higher in GDM women as compared to the NGT participants at three test points (p < 0.01). Spearman's correlation analysis showed that serum SFRP4 levels were significantly positively correlated with ficolin-3 during the early and late second-trimester and third-trimester of pregnancy. The elevated SFRP4 and ficolin-3 concentrations at 16-18 weeks gestation significantly associated with GDM were conformed using binary logistic regression analysis after controlling for other variables [odds ratios (OR) with 95% confidence intervals (CI) for SFRP4: 2.84 (1.78-4.53), p < 0.01; for ficolin-3: 2.45 (1.55-3.88), p < 0.01]. In Conclusions, increased SFRP4 and ficolin-3 levels are significantly associated with GDM development and might be important risk factors for this pregnancy complication.

Low Levels of Immunoglobulins and Mannose-Binding Lectin Are Not Associated With Etiology, Severity, or Outcome in Community-Acquired Pneumonia

Background

Disease severity and outcome in community-acquired pneumonia (CAP) depend on the host and on the challenge of the causal microorganism(s). We measured levels of immunoglobulins (Igs) and complement in 257 hospitalized adults with CAP and examined the association of low levels of Igs or complement to microbial etiology, disease severity, and short-term and long-term outcome.

Methods

Serum Igs were analyzed in blood samples obtained at admission and at 6 weeks postdischarge if admission levels were low. Serum complement deficiencies were screened with a total complement activity enzyme-linked immunosorbent assay (ELISA), with further analyzes performed if justified. Disease severity was assessed by the CURB-65 severity score. Short-term outcome was defined as a composite end point of intensive care unit (ICU) admission and 30-day mortality, and long-term outcome as 5-year all-cause mortality.

Results

At admission, 87 (34%) patients had low levels of at least 1 Ig, with low IgG2 as the most prevalent finding (55/21%). IgG levels were lower in bacterial than viral CAP (8.48 vs 9.97 g/L, P = .023), but low Igs were not associated with microbial etiology. Fifty-five (21%) patients had low lectin pathway activity, of which 33 (13%) were mannose-binding lectin (MBL) deficient. Low admission levels of any Ig or MBL were not associated with disease severity, short-term outcome, or long-term outcome. Excluding patients defined as immunocompromised from analysis did not substantially affect these results.

Conclusion

In hospitalized adults with CAP, low admission levels of Igs or complement were in general not associated with microbial etiology, disease severity, short-term outcome, or long-term outcome.

Association of Low Ficolin-Lectin Pathway Parameters with Cardiac Syndrome X

In patients with typical angina pectoris, inducible myocardial ischaemia and macroscopically normal coronaries (cardiac syndrome X (CSX)), a significantly elevated plasma level of terminal complement complex (TCC), the common end product of complement activation, has been observed without accompanying activation of the classical or the alternative pathways. Therefore, our aim was to clarify the role of the ficolin-lectin pathway in CSX. Eighteen patients with CSX, 37 stable angina patients with significant coronary stenosis (CHD) and 54 healthy volunteers (HC) were enrolled. Serum levels of ficolin-2 and ficolin-3, ficolin-3/MASP-2 complex and ficolin-3-mediated TCC deposition (FCN3-TCC) were determined. Plasma level of TCC was significantly higher in the CSX than in the HC or CHD group (5.45 versus 1.30 versus 2.04 AU/ml, P < 0.001). Serum levels of ficolin-2 and ficolin-3 were significantly lower in the CSX compared to the HC or CHD group (3.60 versus 5.80 or 5.20 μg/ml, P < 0.05; 17.80 versus 24.10 or 26.80 μg/ml, P < 0.05). The ficolin-3/MASP-2 complex was significantly lower in the CSX group compared to the HC group (92.90 versus 144.90 AU/ml, P = 0.006). FCN3-TCC deposition was significantly lower in the CSX group compared to the HC and CHD groups (67.8% versus 143.3% or 159.7%, P < 0.05). In the CSX group, a significant correlation was found between TCC and FCN3-TCC level (r = 0.507, P = 0.032) and between ficolin-3/MASP-2 complex level and FCN3-TCC deposition (r = 0.651, P = 0.003). In conclusion, in patients with typical angina and myocardial ischaemia despite macroscopically normal coronary arteries, low levels of several lectin pathway parameters were observed, indicating complement activation and consumption. Complement activation through the ficolin-lectin pathway might play a role in the complex pathomechanism of CSX.

An electrochemical immunosensor for quantitative detection of ficolin-3

Diabetes mellitus (DM) is one of the most common metabolic disorders in the world, of which more than 90% is type-2 diabetes mellitus (T2DM). There is a rather urgent need for reliable, sensitive and quick detection techniques in clinical application of T2DM. Ficolin-3 is a potential biomarker of T2DM, because serum ficolin-3 levels are associated with insulin resistance and predict the incidence of T2DM. Herein, a sandwich-type electrochemical immunosensor was developed for the detection of ficolin-3 in human serum. Cyclic voltammetry and the amperometric current versus time were used to characterize the performance of the immunosensor. Under optimal conditions, the detection limitation of ficolin-3 was 100 ng ml(-1) and the linear dynamic range was between 2 and 50 μg ml(-1). The method has ideal accuracy, excellent stability and selectivity and has wide application prospects in clinical research.

Activation of the ficolin-lectin pathway during attacks of hereditary angioedema

BACKGROUND

The activation of plasma enzyme systems is insufficiently controlled in hereditary angioedema due to the deficiency of C1-inhibitor (C1-INH) (HAE-C1-INH). Recently, it was suggested that the ficolin-lectin pathway (ficolin-LP) might play a more dominant role than the mannose-binding lectin-lectin pathway in the pathomechanism of HAE-C1-INH.

OBJECTIVE

Because the role of the ficolin-LP during edematous attacks is still enigmatic, we analyzed its activity during such episodes.

METHODS

Thirty-five patients with HAE-C1-INH, who have experienced severe attacks on 106 occasions, were enrolled. We analyzed blood samples drawn during attacks, and obtained 35 samples from the same patients during symptom-free periods. The serum levels of ficolin-2, ficolin-3, MASP-2, ficolin-3/MASP-2 complex, C1-INH, and C4, as well as the extent of ficolin-3-mediated terminal complement complex (FCN3-TCC) deposition, were measured using ELISA-based methods.

RESULTS

Levels of MASP-2 and of the ficolin-3/MASP-2 complex were elevated (P < .0001 and .033, respectively), whereas that of FCN3-TCC was lower (P < .0001) during attacks than during the symptom-free period. During symptom-free periods, FCN3-TCC deposition was significantly related to concentrations of ficolin-3 (R = 0.2778; P = .0022), antigenic C1-INH (R = 0.3152; P = .0006), and C4 (R = 0.5307; P < .0001). Both ficolin-3 and MASP-2 levels correlated inversely with the time from the onset of the attack until blood sampling.

CONCLUSIONS

There is a marked heterogeneity of the pathomechanism and development of hereditary angioedema attacks in different patients. Our results suggest that the activation of the ficolin-LP may deplete the innately low level of C1-INH and thus, it may contribute to the uncontrolled activation of plasma cascade systems, and thereby to edema formation.

Ficolin-3-mediated lectin complement pathway activation in patients with subarachnoid hemorrhage

OBJECTIVES

To assess the involvement of ficolin-3, the main initiator of the lectin complement pathway (LCP), in subarachnoid hemorrhage (SAH) pathology and outcome.

METHODS

In this preliminary exploratory study, plasma concentration of ficolin-3 and of ficolin-3-mediated functional LCP activity was measured, along with that of other LCP initiators (mannose-binding lectin, ficolin-2, and ficolin-1), C3 activation products, and soluble C5b-9 terminal complex, in a prospective cohort of 39 patients with SAH and 20 healthy controls. The following parameters were recorded: SAH severity, assessed using the World Federation of Neurosurgical Societies grading scale; vasospasm, defined as neuro-worsening with angiographic confirmation of vessel narrowing; cerebral ischemia, defined as hypodense lesion on CT scan performed before discharge; and 6-month outcome, assessed using the Glasgow Outcome Scale.

RESULTS

In patients, no changes were detected for ficolin-3 compared with controls. Notably, however, ficolin-3-mediated functional LCP activity was reduced. Low levels of plasma ficolin-3 and ficolin-3-mediated functional LCP activity were related to SAH severity, vasospasm, and cerebral ischemia. Moreover, ficolin-3 functional LCP activity was decreased in patients with unfavorable outcome.

CONCLUSION

Our data provide evidence that LCP is activated after SAH and that the actual plasma concentrations of ficolin-3 reflect the severity of brain injury as evaluated by clinical and structural parameters. These results support the idea that ficolin-3-mediated functional LCP activity may be targeted to control injury progression in SAH.