Serum Amyloid P Component Levels Research Articles

Novel Selective Quantification of Zinpentraxin Alfa Biotherapeutic in the Presence of Endogenous Isomer in Plasma Samples of Idiopathic Pulmonary Fibrosis Patients Using Immunoaffinity LC–MS

Idiopathic pulmonary fibrosis (IPF) is a progressive fatal interstitial lung disease that affects three million patients worldwide and currently without an effective cure. Zinpentraxin alfa, a recombinant human pentraxin-2 (rhPTX-2) protein, has been evaluated as a potential drug candidate for the treatment of IPF. Clinical pharmacokinetic analysis of zinpentraxin alfa has been challenging historically due to interference from serum amyloid P component (SAP), an endogenous human pentraxin-2 protein. These molecules share an identical primary amino acid sequence and glycan composition; however, zinpentraxin alfa possesses α2,3-linked terminal sialic acid residues while SAP is an α2,6-linked isomer. By taking advantage of this only structural difference, we developed a novel assay strategy where α2,3-sialidase was used to selectively hydrolyze α2,3-linked sialic acid residues, resulting in desialylated zinpentraxin alfa versus unchanged sialylated SAP, following an immunoaffinity capture step. Subsequent tryptic digestion produced a unique surrogate asialo-glycopeptide from zinpentraxin alfa and allowed specific quantification of the biotherapeutic in human plasma. In addition, a common peptide shared by both molecules was selected as a surrogate to determine total hPTX-2 concentrations, i.e., sum of zinpentraxin alfa and SAP. The quantification methods for both zinpentraxin alfa and total hPTX-2 were validated and used in pharmacokinetic assessment in IPF patients. The preliminary results suggest that endogenous SAP levels remained largely constant in IPF patients throughout the treatment with zinpentraxin alfa. Our novel approach provides a general bioanalytical strategy to selectively quantify α2,3-sialylated glycoproteins in the presence of their corresponding α2,6-linked isomers.Graphical

Serum amyloid P component (SAP) modulates antidepressant effects through promoting membrane insertion of the serotonin transporter.

Serum amyloid P component (SAP) is a universal constituent of human amyloid deposits including those in Alzheimer's disease. SAP has been observed to be elevated in patients with depression, and higher SAP levels are associated with better response to the antidepressant escitalopram. The mechanisms underlying these clinical observations remain unclear. We examined the effect of SAP on serotonin transporter (SERT) expression and localization using Western blot, confocal microscopy, and positron emission tomography with the radioligand [11C]DASB. We also investigated the effect of SAP on treatment response to escitalopram in mice with the forced swim test (FST), a classical behaviour paradigm to assess antidepressant effects. SAP reduced [11C]DASB binding as an index of SERT levels, consistent with Western blots showing decreased total SAP protein because of increased protein degradation. In conjunction with the global decrease in SERT levels, SAP also promotes VAMP-2 mediated SERT membrane insertion. SAP levels are correlated with behavioural despair and SSRI treatment response in mice with FST. In MDD patients, the SAP and membrane SERT levels are correlated with response to SSRI treatment. SAP has complex effects on SERT levels and localization, thereby modulating the effect of SSRIs, which could partially explain clinical variability in antidepressant treatment response. These results add to our understanding of the mechanism for antidepressant drug action, and with further work could be of clinical utility.

Serum amyloid P component and pro-platelet basic protein in extracellular vesicles or serum are novel markers of liver fibrosis in chronic hepatitis C patients.

Extracellular vesicles (EVs) contain proteins, mRNAs, and microRNAs, and their cargos have emerged as novel diagnostic markers in various diseases. We aimed to discover novel and noninvasive biomarkers of liver fibrosis by proteomic analysis using serum EVs in patients with chronic hepatitis C. We performed shotgun proteomics using serum EVs isolated from 54 patients with histologically assessed liver fibrosis. Shotgun proteomics identified a total of 974 proteins, and 445 proteins were detected in more than half of the patients. Among them, a total of 9 proteins were identified as proteins that tended to increase or decrease with liver fibrosis with a significance of p<0.005 and that were different between F1-2 patients and F3-4 patients with a significance of p<0.01. Among the 9 proteins, targeted proteomics using serum EVs isolated from the sera of another 80 patients with histologically assessed liver fibrosis verified that serum amyloid P component (SAP) and pro-platelet basic protein (PPBP) levels in EVs significantly decreased with the progression of liver fibrosis and were significantly lower in F3-4 patients than in F1-2 patients. The diagnostic accuracies of SAP and PPBP in EVs for the liver fibrosis stage were comparable to those of type IV collagen 7S, hyaluronic acid, and the fibrosis-4 index (FIB-4 index). Moreover, serum SAP and PPBP levels correlated with the levels in EVs, and the ability of serum SAP and PPBP to diagnose liver fibrosis stage was also comparable to the abilities of type IV collagen 7S, hyaluronic acid, and the FIB-4 index. In conclusion, proteomic analysis of serum EVs identified SAP and PPBP as candidate biomarkers for predicting liver fibrosis in patients with chronic hepatitis C. In addition, SAP and PPBP levels in serum are strongly correlated with those in EVs and could represent markers of liver fibrosis.

Serum amyloid P component level is associated with clinical response to escitalopram treatment in patients with major depressive disorder

Serum amyloid P component (SAP) is a universal constituent of human amyloid deposits, which has been implicated in Alzheimer's disease and major depressive disorder (MDD). However, the relationship between SAP level and depression severity remains obscure. The aims of this study were to investigate how SAP is involved in depression and to explore the association between SAP level and antidepressant treatment response. Patients with MDD (n = 85) who received escitalopram monotherapy for 8–12 weeks were selected from a multicenter open-label randomized clinical trial. The same number of healthy controls was recruited. Depression severity was measured according to the Hamilton Depression Rating Scale (HAMD-17) at baseline and weeks 4, 8, and 12. The plasma levels of SAP were measured at baseline, week 2 and week 12. As a result, baseline levels of SAP were significantly higher in depressed patients than in control subjects (p < 0.001). SAP levels at baseline were negatively associated with depression severity after escitalopram treatment (p < 0.05), and the changes in SAP levels from baseline to week 12 were highly correlated with the severity of depressive symptoms based on the HAMD-17 score (p < 0.05). Interestingly, treatment with escitalopram significantly decreased the plasma levels of SAP in females, but not in males. Altogether, our results suggest that SAP not only involved in the pathobiology of depression but also mediates the action of antidepressant medications.

Proteomics Approach Identifies Factors Associated With the Response to Low-Density Lipoprotein Apheresis Therapy in Patients With Steroid-Resistant Nephrotic Syndrome.

Low-density lipoprotein apheresis (LDL-A) has been shown to reduce proteinuria in a subgroup of nephrotic syndrome patients refractory to immunosuppressive therapy. Factors influencing the efficacy of LDL-A in nephrotic syndrome are completely unknown. Using a proteomics approach, we aimed to identify biological markers that predict the response to LDL-A in patients with steroid-resistant nephrotic syndrome (SRNS). Identification of plasma proteins bound to the dextran-sulfate column at the first session of LDL-A was determined by mass spectrometry. To investigate biological factors associated with the response to LDL-A, we compared profiles of column-bound proteins between responders (defined by more than 50% reduction of proteinuria after the treatment) and non-responders by 2-dimensional gel electrophoresis (2-DE) coupled to mass spectrometry in seven patients with SRNS. Evaluation of proteins adsorbed to LDL-A column in patients with SRNS revealed the identity of 62 proteins, which included apolipoproteins, complement components, and serum amyloid P-component (SAP). Comparative analysis of the column-bound proteins between responders and non-responders by 2-DE demonstrated that apolipoprotein E (APOE) and SAP levels were increased in non-responders as compared with responders. These results were confirmed by western blotting. Moreover, serum levels of APOE and SAP were significantly higher in the non-responder group than in the responder group by ELISA. Our data provide comprehensive analysis of proteins adsorbed by LDL-A in SRNS, and demonstrate that the serum levels of APOE and SAP may be used to predict the response to LDL-A in these patients.

Serum Amyloid P-component Level May be a Biomarker for Lung Toxicities and Overall Survival after Thoracic Radiotherapy for Non-small Cell Lung Cancer.

Serum amyloid P-component (SAP) contributes to the clearance of apoptotic cells. As one of the main acute-phase reactants, SAP regulates key aspects of inflammation and sets a threshold for immune cell activation. This study aimed to investigate the association of SAP levels with symptomatic lung toxicities after thoracic radiotherapy (TRT) and overall survival (OS) in non-small lung cancer (NSCLC) patients. The SAP level at diagnosis and during TRT was evaluated by ELISA in 113 clinically inoperable NSCLC patients. Data of radiation pneumonitis (RP)/lung fibrosis, and OS were recorded. The mean ± SEM values of SAP levels at baseline, week 2, and week 4 during TRT were 83.8 ± 6.4, 36.7 ± 4.8, and 36.5 ± 3.4 μg/mL, respectively (p < 0.0001). Using the median value (83.0 μg/mL) as a cutoff, patients with higher baseline SAP level had longer OS than those with lower SAP level (58.2 vs. 23.1 months, p = 0.044). Baseline SAP level, gender, pathology and BED10 were significantly associated with OS in univariate analysis, while only baseline SAP level, pathology, and BED10 were found to be prognostic for OS in multivariate analysis. Patients with symptomatic RP had lower SAP levels than those with no or mild RP (82.7 ± 7.3 vs. 96.8 ± 4.8 μg/mL, p = 0.024). The baseline SAP level can be used to predict symptomatic radiation pneumonitis and was prognostic for survival after TRT for NSCLC patients.

Serum Amyloid P-Component Prevents Cardiac Remodeling in Hypertensive Heart Disease.

The potential for serum amyloid P-component (SAP) to prevent cardiac remodeling and identify worsening diastolic dysfunction (DD) was investigated. The anti-fibrotic potential of SAP was tested in an animal model of hypertensive heart disease (spontaneously hypertensive rats treated with SAP [SHR - SAP] × 12weeks). Biomarker analysis included a prospective study of 60 patients with asymptomatic progressive DD. Compared with vehicle-treated Wistar-Kyoto rats (WKY-V), the vehicle-treated SHRs (SHR-V) exhibited significant increases in left ventricular mass, perivascular collagen, cardiomyocyte size, and macrophage infiltration. SAP administration was associated with significantly lower left ventricular mass (p < 0.01), perivascular collagen (p < 0.01), and cardiomyocyte size (p < 0.01). Macrophage infiltration was significantly attenuated in the SHR-SAP group. Biomarker analysis showed significant decreases in SAP concentration over time in patients with progressive DD (p < 0.05). Our results indicate that SAP prevents cardiac remodeling by inhibiting recruitment of pro-fibrotic macrophages and that depleted SAP levels identify patients with advancing DD suggesting a role for SAP therapy.

Determination of serum amyloid P component in seminal plasma and correlations with serum hormone levels in young, healthy men

Serum amyloid P component (SAP) belongs to the pentraxin family of proteins. SAP is evolutionary conserved, and involved in amyloidosis, innate immunity, inflammation, and apoptosis. We have previously described SAP in the male reproductive tract, where it occurs in seminal fluid, on spermatozoa, and in epididymal, seminal vesicle, and prostate tissue. In the present investigation, our aim was to characterize SAP in male reproduction. In short, we developed and evaluated an immunoassay, analysed the concentration of SAP in seminal plasma and serum in samples from healthy men (N = 203), and studied hormonal regulation. SAP in seminal plasma showed a positively skewed distribution and a median concentration of 1.01 mg/L (inter quartile range [IQR] 0.56–1.65 mg/L). SAP in serum had a Gaussian distribution and a median concentration of 40.5 mg/L (IQR 34.2–49.2 mg/L). Furthermore, SAP concentrations in seminal plasma were not correlated with serum concentrations of SAP, testosterone, sex hormone-binding globulin (SHBG), the testosterone/SHBG ratio, inhibin B, or estradiol. Only a weak negative correlation was found between seminal plasma SAP and serum levels of follicle-stimulating hormone (FSH) (Spearman's rho –0.159; p = 0.023) and luteinizing hormone (LH) (Spearman's rho –0.162; p = 0.021). In conclusion, all men investigated had measurable SAP levels in seminal plasma and in serum. SAP concentrations were 40 times lower in seminal fluid than in serum, and there was no correlation between those two variables. It seems that hormonal regulation is not the major pathway regulating seminal plasma SAP, and seminal plasma SAP and serum SAP are not co-regulated.

Amyloid P component as a plasma marker for Parkinson's disease identified by a proteomic approach

Objectives Parkinson's disease (PD) ranks the second among the neurodegenerative disorders. Proteins involved in Parkinson's disease (PD) have been investigated but none as the diagnostic markers in blood. Design and methods In this study, we applied a proteomic strategy, by utilizing two-dimensional electrophoresis and mass spectrometry, to analyze two sample pools of plasma from the healthy individuals and PD subjects. Results IgGκL and human serum amyloid P component (SAP) were found differentially expressed between these pools. SAP level increased by approximately 5-fold in PD samples, and the ELISA procedure revealed a significant ( P < 0.001) increase in SAP concentration (65.9 ± 18.7 μg/mL) in the plasma of PD subjects (healthy individuals, 35.0 ± 12.5 μg/mL), with sensitivity of 94.1% and specificity of 87.5%. Conclusion Our results indicated a potential feasibility of plasma SAP as a marker to approach PD.

Accumulation and expression of serum amyloid P component in human atherosclerotic lesions

Serum amyloid P component (SAP) is a member of pentraxins. Previous studies indicate that SAP exists in human atherosclerotic aortic intima and the plasma SAP levels are associated with cardiovascular disease. In this study, we characterized SAP in normal and atherosclerotic intima, investigated the source of SAP in atherosclerotic lesions, and assessed the effect of SAP on HDL function. Immunohistochemical staining and electroimmunoassay indicated that SAP is not present in normal aortic intima which excludes the possibility that SAP non-specifically deposits in aortic intima via its binding to microfibrils. Notably, SAP levels are correlated with the severity of atherosclerotic lesions. Fast protein liquid chromatography (FPLC) and Western blot analysis revealed that SAP exists in atherosclerotic lesions in multiple forms. Soluble SAP accumulates in the lesions as decamer in free or bound forms via ligand-binding to its ligand(s). Insoluble SAP accumulates in the lesions in covalent-bound forms conjugated to collagen/collagen-like substances via disulfide (–S–S–) bonds. In situ hybridization and RT-PCR analysis revealed that SAP is generated in atherosclerotic lesions, at least partly, by macrophages and smooth muscle cells in neointima. Functional analysis demonstrated that SAP associated with HDL promotes SR-BI-dependent cholesterol efflux and lipid-free SAP enhances ABCA1-dependent cholesterol efflux. In conclusion, our findings demonstrate that SAP is specifically accumulated and expressed in atherosclerotic lesions. SAP may be involved in cholesterol clearance through its role in promoting cholesterol efflux.

Serum Amyloid P Component as a Biomarker in Mild Cognitive Impairment and Alzheimer’s Disease

Background: Serum amyloid P component (SAP), present in amyloid-β (Aβ) plaques in Alzheimer’s disease (AD), may protect Aβ deposits against proteolysis, thereby promoting plaque formation. The aim was to investigate if SAP levels in cerebrospinal fluid (CSF) and serum can be used to discriminate controls, AD and mild cognitive impairment (MCI) patients, and to identify incipient AD among MCI patients. Methods: SAP levels in CSF and serum were determined in 30 controls, 67 MCI and 144 AD patients. At follow-up, 39 MCI patients had progressed to dementia, while 25 had remained stable (mean follow-up time: 2.6 ± 1.0 and 2.1 ± 0.8 years). Results: Cross-sectionally no differences were found in SAP levels in CSF and serum between the groups. MCI patients that had progressed to dementia at follow-up had lower CSF SAP levels (13 mg/l, range 3.3–199.3 mg/l) than MCI nonprogressors (20.2 mg/l, range 7.0–127.7 mg/l; p < 0.05). A low CSF SAP level was associated with a 2-fold increased risk of progression to AD (hazard ratio = 2.2; 95% confidence interval = 0.9–5.4). Conclusion: Our data suggest that measurement of CSF SAP levels can aid in the identification of incipient AD among MCI patients.

Sequential measurement of the murine acute-phase protein serum amyloid P component (SAP) as an indicator of graft-versus-host disease following allogeneic bone marrow transplantation in mice

Murine models of bone marrow transplantation (BMT) are used commonly for studies of the pathogenesis and treatment of graft-versus-host disease (GVHD). We report here that the sequential measurement of the mouse acute-phase protein SAP can be used to provide a sensitive, quantitative index of the severity of GVHD. Thirty mice underwent allogeneic, and a further 30 syngeneic BMT. GVHD was assessed in vivo by clinical appearances and weight change, and post mortem by histology and calculation of splenic indices. Blood was obtained twice/week for SAP measurement and blood culture. In all mice an initial rise in SAP levels due to irradiation was followed by a return to baseline. Thereafter in syngeneic marrow recipients levels remained low. In contrast, after allogeneic BMT SAP levels rose progressively as mice developed GVHD, reaching a peak of 135 micrograms/ml prior to death, from a nadir at day 20 of 15 micrograms/ml. Mice with high splenic indices and histological evidence of severe GVHD had significantly higher SAP levels than mice with mild GVHD (P = 0.0002). Elevation in SAP levels occurred independently of bacteraemia. We conclude that in murine BMT sequential measurement of SAP provides an objective means of assessing GVHD in vivo.

Acute phase response induction by cancer treatment with photodynamic therapy

Inflammation and immunity development are well recognized as responses to tumor treatment by photodynamic therapy (PDT). To demonstrate that another major host response effector process, acute phase response, may be also induced by this cancer treatment modality, the expression of serum amyloid P component (SAP) acknowledged as a hallmark acute phase reactant in the mouse was investigated following PDT of murine FsaR fibrosarcomas. The results reveal almost 150-fold increase in the expression of SAP gene in the liver of mice bearing tumors treated by Photofrin-mediated PDT, while serum SAP levels increased around 50-fold at the peak interval about 24 hr post PDT. The same tumor treatment induced also the liver gene upregulation and serum levels elevation of another established acute phase reactant, mannose-binding lectin A (MBL-A). Both SAP and MBL-A were found to accumulate in PDT-treated tumors, but this includes local production because their genes in these tumor tissues were upregulated as well. Gene encoding C-reactive protein (CRP) was also upregulated almost 7-fold in the same tumor tissues, suggesting a rare example of CRP participation in host response of the mouse. Interleukin-6 and glucocorticoid hormones were identified as major mediators promoting tumor PDT-induced upregulation of liver SAP gene. Moreover, glucocorticoids were found to act as critical inducers of SAP gene upregulation in PDT-treated tumors. The study definitely proves the occurrence of a strong acute phase response following tumor PDT, and reveals that glucocorticoid hormones released during this development impact the expression of host response-relevant genes in PDT-treated tumors.

Acute phase response in mice experimentally infected with Trypanosoma congolense: A molecular gauge of parasite–host interaction

Mice infected with Trypanosoma congolense developed a severe anaemia 1 week after infection, which persisted till treatment with diminazine aceturate when the packed cell volume (PCV) recovered to pre-infection levels. This was accompanied by a marked increase in the plasma levels of the acute phase proteins (APP), serum amyloid P-component (SAP) and haptoglobin (Hp). The initial peak levels of Hp and SAP were attained 7 and 12 days post-infection (DPI), respectively. Thereafter SAP levels decreased significantly to near pre-infection levels, but later increased even after treatment to give a second peak 34 DPI after which there was a decline till the study was terminated. The Hp levels on the other hand decreased to an intermediate level after the initial peak increasing to a second peak 22 DPI. Thereafter Hp decreased significantly following diminazine aceturate treatment to reach pre-infection levels within 5 days post-treatment. This indicates that T. congolense-infected mice develop severe anaemia accompanied by an acute phase response leading to an increase in SAP and Hp but that following treatment divergent responses occurred indicating differences in the pathways for stimulation of the APP. Haptoglobin was shown to be an earlier indicator of infection and a better marker in monitoring the response to treatment.

Normal circulating serum amyloid P component concentration in systemic sclerosis

The observation of reduced circulating concentrations of the constitutive plasma pentraxin protein, serum amyloid P component (SAP), in serum samples obtained from a small number of patients with systemic sclerosis (SSc) has been reported as confirmation of an antifibrotic role of this protein. Because neither sustained SAP depletion in humans nor SAP deficiency in mice is associated with fibrosis, we sought to establish rigorously the serum SAP concentration in well-characterized patients with SSc. Serum concentrations of SAP were measured by electroimmunoassay in a cross-sectional cohort of 20 patients with diffuse cutaneous SSc and 12 patients with limited cutaneous SSc, and in a separate 12-month longitudinal cohort of 13 patients with diffuse disease and 37 patients with limited disease. The extent and severity of disease were characterized in detail at the time of serum sampling. Serum concentrations of the classic acute-phase reactants, C-reactive protein and serum amyloid A protein, were measured by immunonephelometric assays. SAP values were entirely within the normal range, regardless of the extent and severity of disease, apart from a very few isolated raised values associated with acute intercurrent complications causing major acute-phase responses. We observed no reduced circulating concentrations of SAP in patients with SSc, nor any evidence of an association between SAP levels and the extent or severity of fibrosis.

Serum amyloid P-component in murine tuberculosis: induction kinetics and intramacrophage Mycobacterium tuberculosis growth inhibition in vitro

Serum amyloid P-component (SAP), a pentraxin, is known to play an important role in innate immunity to microbial infections; however, nothing is known about it during tuberculosis (TB). Mice intratracheally infected with Mycobacterium tuberculosis Erdman, showed peak SAP levels (442 ± 58.2 μg/ml) on day 21, which declined to background levels by day 60. Their serum interleukin-6 levels paralleled SAP levels, whereas, their serum transforming growth factor-β levels were paradoxical. During the acute phase of infection, the SAP levels positively correlated with the lung mycobacterial load. Purified mouse SAP (1–50 μg/ml) treatment of M. tuberculosis-infected alveolar macrophages (AMs), in vitro, inhibited their intracellular mycobacterial growth; maximum inhibition (1.1 log 10 CFU reduction) occurred at 10 μg/ml, and a 4-day treatment appeared optimal. Treatment of AMs with both rabbit anti-mouse SAP polyclonal antibody and mannose-derived simple sugars, separately, blocked the SAP-induced inhibition of mycobacterial growth. The mycobacterial growth inhibition appeared to be nitric oxide (NO)-dependent as NO synthase inhibitors, both aminoguanidine and N G-monomethyl- l-arginine, annulled it. Further, SAP treatment of infected AMs induced significant ( P < 0.05) elaboration of nitrite (72.1 ± 8.3 nM/ml), compared to the controls, and these AMs showed augmented expression of inducible NO synthase. This first study demonstrates that during murine TB the SAP levels were increased, and purified mouse SAP inhibited the intra-AM M. tuberculosis growth, in vitro, apparently via NO-dependent mechanism(s). SAP may thus contribute both to the pathogenesis and pulmonary innate immunity in TB.

Acute-phase reactants during murine tuberculosis: Unknown dimensions and new frontiers

Serum amyloid P-component (SAP) plays important roles in host defense during various infectious diseases; however, nothing is known in tuberculosis (TB). To study the SAP response of Mycobacterium tuberculosis H37Rv- and H37Ra-infected mice, and to determine the effect(s) of purified mouse SAP both on their intra-alveolar macrophage (AM) uptake and intra-AM growth in vitro. The SAP levels of mice intratracheally infected with M. tuberculosis H37Rv and H37Ra were determined by ELISA. Mycobacterial AM uptake and intra-AM growth in vitro were determined using fluorescence microscopy and plating, respectively. M. tuberculosis H37Rv-infected mice showed significantly (p < 0.05) increased SAP levels (352.8+/-36.1 microg/ml) with compared mice infected with M. tuberculosis H37Ra (170+/-18.5 microg/ml). During the acute phase of both these infections, enhanced SAP levels correlated with the lung mycobacterial load. In vitro, purified mouse SAP (1-80 microg/ml) inhibited the AM uptake of both the mycobacteria in a concentration-dependent manners to a similar extent; 20 microg/ml SAP appeared optimal. Mycobacterial uptake inhibition was divalent cation- and pH-dependent, and was unaffected both by heat-inactivated and deglycosylated SAP, separately. Curiously, purified mouse SAP (1-80 microg/ml), in a concentration-dependent manner, inhibited the intra-AM growth of both M. tuberculosis H37Rv and H37Ra in vitro; the effect was 0.8 log10 CFUs greater on the latter. Both the mannose-based simple sugars and rabbit anti-mouse SAP polyclonal antibody, separately, annulled the inhibition of mycobacterial growth in vitro. This initial study demonstrates that both the SAP response of M. tuberculosis-infected mice, and the SAP-induced intra-AM mycobacterial growth inhibition in vitro were apparently dependent on mycobacterial virulence.

CSF markers related to pathogenetic mechanisms in Alzheimer's disease.

Serum amyloid P component (SAP) and complement C1q are found highly co-localized with extracellular fibrillar amyloidbeta (Abeta) deposits in Alzheimer's disease (AD) brain. Conflicting data were reported earlier about the cerebrospinal fluid (CSF) levels of SAP and C1q in AD compared to controls. The objective of the present study was to compare the levels of Abeta(1-42), tau, C1q and SAP in CSF of a well characterized group of AD patients and controls, and to assess the association with dementia severity. Significantly decreased CSF levels of Abeta(1-42) were observed in the AD group (480 +/- 104 ng/L) as compared to controls (1,040 +/- 213 ng/L), whereas tau levels were significantly higher in patients with AD (618 +/- 292 ng/L) than in controls (277 +/- 136 ng/L). Combining the results of Abeta(1-42) and tau measurements resulted in a clear separation between the AD group and the controls. No significant differences in CSF levels of SAP and C1q were observed between the well characterized AD patients and non demented control group. Furthermore, we could not demonstrate a correlation between SAP and C1q CSF levels and the severity of the disease, expressed in Mini-Mental State Examination (MMSE) scores. Therefore, in our opinion these factors can be excluded from the list of potentially interesting biomarkers for AD diagnosis and progression.

Serological evidence for an inflammatory response in murine scrapie.

Transmissible spongiform encephalopathies (TSEs) are initiated by a novel kind of agent that produces characteristic degenerative changes in the brain without a detectable systemic inflammatory response or serological changes. A murine scrapie model was evaluated for changes in plasma concentration of serum amyloid P component (SAP), a protein that is up-regulated in infected and/or injured mice during the acute phase response (APR). C57BL10 and IRW mice inoculated with scrapie brain developed clinical scrapie 125-150 days later. At this time, concentration of plasma SAP increased in most of them. The SAP level increased > or =3-fold in >80% of the scrapie-affected C57BL10 mice and IRW male mice. A similar increase was found in <3% of respective nonscrapie control mice. The up-regulation of mouse SAP during clinical scrapie provides evidence for the activation of a systemic APR in TSE, a serological change that may be clinically useful.

INCREASED SERUM AMYLOID A LEVELS REFLECT COLITIS SEVERITY AND PRECEDE AMYLOID FORMATION IN IL-2 KNOCKOUT MICE

The lack of sensitive and relatively non-invasive measures has hampered monitoring the clinical course of spontaneously developing colitis in IL-2-deficient (−/−) mice. We selected (i) to study the correlation of the acute phase plasma proteins serum amyloid A (SAA) and serum amyloid P component (SAP) levels with colonic disease and (ii) to characterize the amyloidosis in the IL-2−/−animals. IL-2−/−mice exhibited increasing severity of gross intestinal inflammation with age, confined to the distal colon. Histologically, the colonic disease score increased serially in IL-2−/−animals. Wild-type mice showed no activity, while 16-week-old IL-2+/−animals had minimal colitis with small ulcers and lamina propria inflammatory infiltrate. Periportal hepatitis was present and positive Congo red staining indicated amyloidosis of the liver and spleen in 16 week IL-2−/−mice. SAA immunostaining in the liver and spleen was increased in the 8 week and 16 week IL-2−/−and 16 week IL-2+/−animals indicating AA amyloid deposits. Plasma SAA and SAP levels were markedly elevated, and generally preceded the onset of colitis and reflected its severity. Northern analysis showed markedly increased SAA expression in the liver and intestine of IL-2−/−and intestine of IL-2+/−16-week-old animals. Increased intestinal expression of SAA3 (lamina propria macrophages) indicates local inflammation in IL-2+/−animals at 16 weeks. Treatment of 3-week-old animals with systemic IL-2 or IL-1 receptor antagonist (IL-1ra) delayed inflammation, postponed the increase in SAA levels and minimized disease onset. These results further demonstrate that IL-2 plays a significant role in normal immune responses in the body and that plasma SAA levels both reflect colonic disease severity and may indicate subclinical disease in both IL-2−/−and IL-2+/−mice. Furthermore. The mechanism of IL-2-deficient induced colitis appears to be mediated in part through the increase in IL-1. In addition, the IL-2−/−mouse of spontaneous enterocolitis may provide a unique system for studying spontaneously developing AA amyloidosis.