Elevated Serum Amyloid A Levels Research Articles

Structural studies of a serum amyloid A octamer that is primed to scaffold lipid nanodiscs.

Serum amyloid A (SAA) is a highly conserved acute-phase protein that plays roles in activating multiple pro-inflammatory pathways during the acute inflammatory response and is commonly used as a biomarker of inflammation. It has been linked to beneficial roles in tissue repair through improved clearance of lipids and cholesterol from sites of damage. In patients with chronic inflammatory diseases, elevated levels of SAA may contribute to increased severity of the underlying condition. The majority of circulating SAA is bound to lipoproteins, primarily high-density lipoprotein (HDL). Interaction with HDL not only stabilizes SAA but also alters its functional properties, likely through altered accessibility of protein-protein interaction sites on SAA. While high-resolution structures for lipid-free, or apo-, forms of SAA have been reported, their relationship with the HDL-bound form of the protein, and with other possible mechanisms of SAA binding to lipids, has not been established. Here, we have used multiple biophysical techniques, including SAXS, TEM, SEC-MALS, native gel electrophoresis, glutaraldehyde crosslinking, and trypsin digestion to characterize the lipid-free and lipid-bound forms of SAA. The SAXS and TEM data show the presence of soluble octamers of SAA with structural similarity to the ring-like structures reported for lipid-free ApoA-I. These SAA octamers represent a previously uncharacterized structure for lipid-free SAA and are capable of scaffolding lipid nanodiscs with similar morphology to those formed by ApoA-I. The SAA-lipid nanodiscs contain four SAA molecules and have similar exterior dimensions as the lipid-free SAA octamer, suggesting that relatively few conformational rearrangements may be required to allow SAA interactions with lipid-containing particles such as HDL. This study suggests a new model for SAA-lipid interactions and provides new insight into how SAA might stabilize protein-lipid nanodiscs or even replace ApoA-I as a scaffold for HDL particles during inflammation.

Serum alpha 1-acid glycoprotein and interleukin-8 elevations in felines with localized and metastatic tumors.

This study aimed to investigate the expression of acute phase proteins and plasma cytokines in cats with various tumor types and varying metastatic statuses. 5 clinically healthy cats and 22 cats with neoplastic disease that underwent CT imaging before treatment were enrolled. Patients were grouped based on their tumor types and metastatic status. Blood samples were collected from all cats for general blood analyses before they underwent CT imaging. The remaining plasma sample was frozen for subsequent alpha 1-acid glycoprotein (AGP), serum amyloid A (SAA), and feline cytokine panel measurements. These results were compared with those of healthy cats as well as between metastatic status and tumor types. Only 4 cats (18%) exhibited elevated SAA levels, whereas 16 (73%) showed elevated AGP levels. AGP was significantly increased in cats with tumors (P = .016), while SAA was not. Only IL-8 showed a significant difference (P = .002) between cats with primary tumors and those with radiologically suspected tumor metastasis. While AGP is a more prominent biomarker than SAA in cats with tumors, a significant elevation of AGP and SAA levels in association with metastasis and specific tumor types could not be identified. Alternatively, further investigation is warranted to evaluate the potential significance of IL-8 in tumor progression and metastasis.

Renal involvement in monogenic autoinflammatory diseases: A narrative review.

Autoinflammatory diseases (AIDs) are mostly caused by dysfunctions in single genes encoding for proteins with a prominent role in the regulation of innate immunity, such as complement factors, inflammasome components, tumour necrosis factor (TNF)-α, and proteins belonging to type I-interferon (IFN) signalling pathways. Due to the deposition of amyloid A (AA) fibrils in the glomeruli, unprovoked inflammation in AIDs frequently affects renal health. In fact, secondary AA amyloidosis is the most common form of amyloidosis in children. It is caused by the extracellular deposition of fibrillar low-molecular weight protein subunits resulting from the degradation and accumulation of serum amyloid A (SAA) in numerous tissues and organs, primarily the kidneys. The molecular mechanisms underlying AA amyloidosis in AIDs are the elevated levels of SAA, produced by the liver in response to pro-inflammatory cytokines, and a genetic predisposition due to specific SAA isoforms. Despite the prevalence of amyloid kidney disease, non-amyloid kidney diseases may also be responsible for chronic renal damage in children with AIDs, albeit with distinct characteristics. Glomerular damage can result in various forms of glomerulonephritis with distinct histologic characteristics and a different underlying pathophysiology. This review aims to describe the potential renal implications in patients with inflammasomopathies, type-I interferonopathies, and other rare AIDs in an effort to improve the clinical course and quality of life in paediatric patients with renal involvement.

Značaj serumskog amiloida A za tok i ishod SARS-CoV-2 infekcije

The occurrence of a new coronavirus, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), quickly became a global threat after it had spread across the continents in just a few months. Over the next three years, it caused infections in over 646.6 million people and resulted in over 6.6 million deaths. As a novel disease, Coronavirus Disease 19 (COVID-19) became the subject of intensive research. Due to various clinical manifestations of the infection with possible fatal outcomes, it became evident that a finer understanding of COVID-19 pathogenesis, clinical manifestations, and complications is necessary. Investigation of acute-phase reaction as a component of the immune system response to infection can be very helpful. Serum amyloid A (SAA) was investigated for this purpose as one of the acute-phase reactants primarily synthesized by the hepatocytes in response to pro-inflammatory cytokines. It has been found that elevated SAA levels were independent factors for gastrointestinal manifestations and liver injury during COVID-19 but also one of the factors in COVID19-associated coagulopathy. Studies showed that SAA levels positively correlate with disease severity and prognosis. Patients with severe infection demonstrated significantly higher levels of SAA. Higher SAA levels were observed in COVID-19 patients with chronic diseases such as diabetes mellitus, hypertension, cerebrovascular diseases, and obesity, all recognized as independent risk factors for critical disease and poor prognosis. Patients with COVID-19 who died had higher levels of SAA than survivors. This short review will summarize current studies and knowledge about SSA in COVID-19, its role in the pathogenesis of SARS-CoV-2 infection, and its clinical usefulness in COVID-19 patients.

Post-translational modification of amyloid a protein in patients with AA amyloidosis

AA amyloidosis is a disease caused by extracellular deposition of insoluble β-pleated sheet fibrils composed of amyloid A (AA) protein, an amino (N)-terminal fragment of serum amyloid A (SAA). The deposits disrupt tissue structure and compromise organ function. Although the disease is systemic, deposition in kidney glomeruli is the most common manifestation. The leading cause of AA amyloidosis is sustained or recurrent inflammation accompanied by elevated levels of SAA. Factors determining the conversion of SAA to AA amyloid fibrils have yet to be fully resolved. Herein, we present liquid chromatography tandem-mass spectrometry (LC-MS/MS) analysis of AA proteins purified from eight patients with AA amyloidosis. For the first time, post-translational modifications (PTM), including carbamylation, acetylation and oxidation, were identified on AA peptides; all eight samples showed some degree of PTM. The amyloid in 6 samples comprised peptides derived from SAA1 with few or none from SAA2, while the other two samples contained both SAA1- and SAA2-derived peptides. N-terminal AA peptides beginning with Arg1 as well as AA peptides starting with Ser2 were present in five of the eight samples, while all or nearly all of the N-terminal peptides in the other three samples lacked Arg1. These data demonstrate that multiple species of AA amyloid proteins can comprise the subunits in amyloid fibrils and raise the possibility that PTM may play a role in fibrillogenesis.

COVID-19 AMONG DIABETES PATIENTS TYPE 2

A total of 74 COVID-19 diabetic patients were enrolled in the study. Twenty-seven patients (36.5%) were severely ill, and ten patients (13.5%) died. Severe patients had higher blood glucose, serum amyloid A (SAA), C reactive protein, and interleukin 6 levels than non-severe patients (P> 0.05). Severe patients had lower levels of albumin, cholesterol, high density lipoprotein, small and dense low density lipoprotein, and CD4 T lymphocyte counts than non-severe patients (P > 0.05). Reduced CD4 21 + T lymphocyte counts (OR = 0.988, 95 percent confidence interval [95 percent CI] 0.979–0.997) and elevated SAA levels (OR = 1.029, 95 percent CI 1.002–1.058) were found as risk variables for COVID- 19 severity with diabetes in a logistic regression analysis (P > 0.05).
 Keywords: COVID-19, Diabetes, Hyperglycemia, Dislipidemia, CD4+ T lymphocyte , follow up symptoms.

A case of Schnitzler\u2019s syndrome without monoclonal gammopathy successfully treated with canakinumab

BackgroundSchnitzler’s syndrome (SchS) is a rare autoinflammatory syndrome with diagnostic challenge and be characterized by chronic urticaria, a monoclonal gammopath, periodic fever and bone pain. In addition to the monoclonal gammopathy, bone abnormalities are often found at the site of bone pain in patients with SchS. The remarkable efficacy of interleukin-1 (IL-1) inhibition was also demonstrated in this syndrome.Case presentationWe describe a case of refractory chronic urticaria presenting with clinical manifestations consistent with SchS without monoclonal gammopathy. A 43-year-old female patient suffering from recurring of urticaria with periodic fever as well as bone pain for the past 4 years. The patient had leukocytosis and elevated levels of C-reactive protein (CRP) and serum amyloid A (SAA). PET/CT (positron emission tomography/computed tomography) and MRI (magnetic resonance imaging) examination revealed hyper-metabolism areas in both femoral bone marrow. Although bone marrow histology revealed no abnormality, urticarial skin lesions shows neutrophilic infiltrations without evidence of vasculitis. We could not exclude the possibility of SchS. The patient had been treated with antihistamines, steroids, omarizumab, colchicine and cyclosporine A, no therapeutic effect was observed. She was started on canakinumab 150 mg subcutaneous injection with 4 weeks interval. Within 48 h after the first injection, the urticarial rash disappeared, and febrile attack and bone pain had not recurred. Elevated levels of serum CRP and SAA were normalized within a week after the first injection of canakinumab.ConclusionsThe current case suggests an important role for IL-1 as a mediator in the pathophysiology of SchS-like refractory urticaria with bine pain. It had been presumed that monoclonal gammopathy may not always present in SchS. It is important to avoid delay in diagnosis and initiation of proper treatment in SchS or autoinflammatory conditions resembling SchS.

Inflammatory and coagulatory markers and exposure to different size fractions of particle mass, number and surface area air concentrations in Swedish iron foundries, in particular respirable quartz

PurposeTo study the relationship between inhalation of airborne particles and quartz in Swedish iron foundries and markers of inflammation and coagulation in blood.MethodsPersonal sampling of respirable dust and quartz was performed for 85 subjects in three Swedish iron foundries. Stationary measurements were used to study the concentrations of respirable dust and quartz, inhalable and total dust, PM10 and PM2.5, as well as the particle surface area and the particle number concentrations. Markers of inflammation, namely interleukins (IL-1β, IL-6, IL-8, IL-10 and IL-12), C-reactive protein, and serum amyloid A (SAA) were measured in plasma or serum, together with markers of coagulation including fibrinogen, factor VIII (FVIII), von Willebrand factor and d-dimer. Complete sampling was performed on the second or third day of a working week after a work-free weekend, and follow-up samples were collected 2 days later. A mixed model analysis was performed including sex, age, smoking, infections, blood group, sampling day and BMI as covariates.ResultsThe average 8-h time-weighted average air concentrations of respirable dust and quartz were 0.85 mg/m3 and 0.052 mg/m3, respectively. Participants in high-exposure groups with respect to some of the measured particle types exhibited significantly elevated levels of SAA, fibrinogen and FVIII.ConclusionsThese observed relationships between particle exposure and inflammatory markers may indicate an increased risk of cardiovascular disease among foundry workers with high particulate exposure.

The prognostic value of serum amyloid A for long-term mortality among patients with subclinical carotid atherosclerosis.

Background and PurposeDespite extensive research in the last decade, the role of serum amyloid A (SAA) in atherogenesis remains highly controversial. The aim of this study was therefore to assess whether SAA is associated with long‐term mortality in patients with subclinical carotid artery disease.MethodsOne thousand sixty‐five patients with neurological asymptomatic carotid atherosclerosis as evaluated by duplex sonography were prospectively followed for cause‐specific mortality.ResultsDuring a median of 11.8 years, a total of 549 deaths, including 362 cardiovascular deaths, were recorded. Patients who died within the follow‐up period had significantly higher baseline SAA serum levels compared to those who survived (12.9 vs 9.5 mg/dL; P < 0.001). In univariable Cox regression analysis, the risk of all‐cause and cardiovascular mortality significantly increased in patients with elevated serum levels of SAA (crude hazard ratio for cardiovascular mortality per increase of 1 SD of SAA levels was 1.14, 95% CI 1.08‐1.22], P < 0.0001). However, SAA lost its significance after adjusting for high‐sensitivity C‐reactive protein (hsCRP), suggesting that SAA might not be directly associated with atherogenesis, but rather be a mere reflection of the individual patient's inflammatory status.ConclusionsSerum amyloid A is not independently associated with (cardiovascular) mortality in patients with subclinical carotid atherosclerosis.

High acute phase protein levels correlate with pulmonary and skin involvement in patients with diffuse systemic sclerosis.

ObjectiveThis study was performed to evaluate the serum amyloid A (SAA) and C-reactive protein (CRP) levels in patients with diffuse systemic sclerosis (dSSc) in relation to a control group, disease duration, and skin and pulmonary involvement.MethodsThis case-control study included 18 patients with early dSSc, 15 patients with late dSSc, and 15 healthy controls. The SAA and CRP levels, modified Rodnan skin score (mRSS), and diffusing capacity of the lungs for carbon monoxide (DLCO) were determined in all patients.ResultsThe SAA and CRP levels were significantly higher in patients with early and late dSSc than in healthy controls. The frequency of detection of elevated SAA and CRP levels was approximately 66% and 85%, respectively. A significant correlation was found between the SAA and CRP levels in patients with dSSc. The SAA and CRP levels were inversely correlated with DLCO. The CRP level was positively correlated with the mRSS.ConclusionsHigh SAA and CRP levels could serve as biomarkers for pulmonary involvement. The serum CRP level accurately reflects the extension of skin thickening in patients with dSSc.

Maternal serum amyloid A level as a novel marker of primary unexplained recurrent early pregnancy loss.

To assess maternal serum amyloid A (SAA) levels among women with primary unexplained recurrent early pregnancy loss (REPL). A prospective study was conducted among women with missed spontaneous abortion in the first trimester at Ain Shams University Maternity Hospital, Cairo, Egypt, between January 21 and December 25, 2014. Women with at least two consecutive primary unexplained REPLs and no previous live births were enrolled. A control group was formed of women with no history of REPL who had at least one previous uneventful pregnancy with no adverse outcomes. Serum samples were collected to measure SAA levels. The main outcome was the association between SAA and primary unexplained REPL. Each group contained 96 participants. Median SAA level was significantly higher among women with REPL (50.0μg/mL, interquartile range 26.0-69.0) than among women in the control group (11.6μg/mL, interquartile range 6.2-15.5; P<0.001). The SAA level was an independent indicator of primary unexplained REPL, after adjusting for maternal age and gestational age (odds ratio 1.12, 95% confidence interval 1.06-1.19; P<0.001). Elevated SAA levels found among women with primary unexplained REPL could represent a novel biomarker for this complication of pregnancy.

Comparing fluorescence-based cell-free assays for the assessment of antioxidative capacity of high-density lipoproteins.

BackgroundPopulation studies have shown an inverse association between high-density lipoprotein (HDL) cholesterol levels and risk of coronary heart disease (CHD). HDL has different functions, including the ability to protect biological molecules from oxidation. Our aim was to evaluate the performance of two fluorescence-based assays in assessing the antioxidative capacity of HDL.MethodsWe compared the antioxidative capacity of HDL with the phospholipid 2’,7’-dichlorodihydrofluorescein (DCF) assay and the dihydrorhodamine 123 (DHR) assay in controls and in subjects at increased risk of CHD, including subjects with established CHD, and subjects with elevated plasma triglycerides (TG), serum amyloid A (SAA), or myeloperoxidase (MPO) levels.ResultsThe antioxidative capacity of HDL, as measured by the DCF assay, was significantly lower in both CHD and high-TG patients than in controls (p < 0.001 and p = 0.004, respectively). Interestingly, the mean antioxidative capacity of HDL in high-SAA subjects was significantly higher (p < 0.03), while in high-MPO subjects was similar to controls. When the DHR assay was used we did not find differences in HDL’s antioxidative capacity between CHD patients and controls but we found higher antioxidative capacity in high-SAA subjects compared to controls.ConclusionsOnly the DCF assay could detect significant differences in the antioxidative capacity of HDL between controls and CHD subjects. Practical use of both assays for the assessment of antioxidative capacity of HDL is limited by the large overlap in values among groups. The antioxidative activity of HDL in patients who have elevated SAA levels needs to be reassessed.

Comparison of serum protein concentrations to clinical observations during lipopolysaccharide (LPS) induced inflammation in swine.

Abstract The serum kinetic profile of the proteins MCP1 (CCL-2), C - reactive protein (CRP), and Serum Amyloid A (SAA) were compared to clinical observations in swine given a single i.v. administration of lipopolysaccharide (LPS; 2 μg/kg). Blood samples were collected at 0, 1, 3, 6, 8, &amp; 24 hr after LPS administration using an in-dwelling catheter inserted prior to LPS administration. Serum protein concentrations were determined using species-specific ELISA. Clinical observations include temperature, respiration rate (RR), skin redness (SR), lethargy, and respiratory character (RC). LPS administration failed to result in elevated CRP and SAA levels. MCP-1 was induced within 1 h of LPS administration, and remained elevated through 8 h, returning to baseline values by 24 h post-LPS. The kinetics of MCP1 protein differ from that of MCP1 mRNA, which exhibits elevated levels through 48 h post LPS (Peters et al, Vet Immol Immunopath, 2014, 148: 236–242). The clinical results suggest that the administered challenge resulted in toxicity beyond the expected systemic inflammatory response. However the results also suggest that MCP1 may be a serum protein biomarker of inflammation associated with severe endotoxicity and RR, RC, SR and lethargy may be clinical measures that can be used to qualify analytical measures such as MCP1 as surrogate endpoints. These results further suggest the model needs to be refined. The discordant regulation of MCP1 protein and mRNA levels suggest additional molecular controls regulating MCP1 protein production.

Occupational exposure levels of bioaerosol components are associated with serum levels of the acute phase protein Serum Amyloid A in greenhouse workers.

BackgroundOccupational exposure to particles may be associated with increased inflammation of the airways. Animal experiments suggest that inhaled particles also induce a pulmonary acute phase response, leading to systemic circulation of acute phase proteins. Greenhouse workers are exposed to elevated levels of bioaerosols. The objective of this study is to assess whether greenhouse workers personal exposure to bioaerosol components was associated with serum levels of the acute phase proteins Serum Amyloid A (SAA) and C-reactive protein (CRP).MethodsSAA and CRP levels were determined in serum sampled repeatedly from 33 greenhouse workers. Blood was drawn repeatedly on Mondays and Thursdays during work weeks. Acute phase protein levels were compared to levels in a comparison group of 42 people and related to individual exposure levels to endotoxin, dust, bacteria, fungi and β-glucan.ResultsSerum levels of SAA and CRP were not significantly different in greenhouse workers and a reference group, or on the two work days. In a mixed model, SAA levels were positively associated with endotoxin exposure levels (p = 0.0007). Results for fungi were not clear. CRP levels were positively associated with endotoxin exposures (p = 0.022). Furthermore, when workers were categorized into three groups based on SAA and CRP serum levels endotoxin exposure was highest in the group with the highest SAA levels and in the group with middle and highest CRP levels. SAA and CRP levels were elevated in workers with asthma.ConclusionGreenhouse workers did not have elevated serum levels of SAA and CRP compared to a reference group. However, occupational exposure to endotoxin was positively associated with serum levels of the acute phase proteins SAA and CRP. Preventive measures to reduce endotoxin exposure may be beneficial.

Serum Amyloid A Level in Egyptian Children with Familial Mediterranean Fever.

Background and Objectives. SAA is an acute-phase reactant detected during an FMF attack or other inflammatory conditions. High SAA levels may increase the risk of amyloidosis. The aim of the study is to measure the serum amyloid A (SAA) level in a group of Egyptian children with familial Mediterranean fever (FMF) and study its various correlates, if any. Methods. The study enrolled seventy-one children with FMF. Results. SAA level was high in 78.9% of the studied patients with a mean of 81.62 ± 31.6 mg/L, and CRP was positive in 31% of patients. There was no significant releation between SAA level and any demographic or clinical manifestation. High SAA was more frequent in V726A allele (16.9%) followed by M694V allele (12.3%). Elevated SAA levels were more frequent in patients on low colchicine doses. Forty-five percent (45%) of patients have low adherence to colchicine therapy. Interpretation and Conclusion. High SAA levels were detected two weeks after last FMF attack in a large percentage of Egyptian FMF children. This indicates that subclinical inflammation continues during attack-free periods, and SAA could be used as a marker of it.

Serum amyloid A is a marker for pulmonary involvement in systemic sclerosis.

Inflammation in systemic sclerosis (SSc) is a prominent, but incompletely characterized feature in early stages of the disease. The goal of these studies was to determine the circulating levels, clinical correlates and biological effects of the acute phase protein serum amyloid A (SAA), a marker of inflammation, in patients with SSc. Circulating levels of SAA were determined by multiplex assays in serum from 129 SSc patients and 98 healthy controls. Correlations between SAA levels and clinical and laboratory features of disease were analyzed. The effects of SAA on human pulmonary fibroblasts were studied ex vivo. Elevated levels of SAA were found in 25% of SSc patients, with the highest levels in those with early-stage disease and diffuse cutaneous involvement. Significant negative correlations of SAA were found with forced vital capacity and diffusion capacity for carbon monoxide. Patients with elevated SAA had greater dyspnea and more frequent interstitial lung disease, and had worse scores on patient-reported outcome measures. Incubation with recombinant SAA induced dose-dependent stimulation of IL-6 and IL-8 in normal lung fibroblasts in culture. Serum levels of the inflammatory marker SAA are elevated in patients with early diffuse cutaneous SSc, and correlate with pulmonary involvement. In lung fibroblasts, SAA acts as a direct stimulus for increased cytokine production. These findings suggest that systemic inflammation in SSc may be linked to lung involvement and SAA could serve as a potential biomarker for this complication.

Endemic and highly prevalent amyloid A amyloidosis in endangered island foxes (Urocyon littoralis) (1139.16)

Critically endangered island foxes develop a systemic amyloidosis with an extraordinarily high prevalence of 32% (mean), and exceeding 40% in some subspecies. Amyloidosis has been recognized in foxes for 15 years. The organs most affected by amyloid are kidney, spleen, vessels, heart, adrenal gland, tongue, oropharynx, and skin. There was an increased risk of amyloidosis found in adults, the San Clemente island subspecies, captively housed foxes, and foxes with neoplasia. In amyloid‐rich tissue, the dominant insoluble protein was a 12‐kDa protein labeled by serum amyloid A (SAA) antibodies that were generated against canine SAA. Mass spectrometry on insoluble proteins from 9 amyloid‐laden samples revealed SAA as the dominant protein, which was not present in control samples. The SAA protein was composed of 111 amino acids and consisted of multiple isoforms, including isoforms unique amongst canids. SAA amyloidosis is typically associated with prolonged elevation of SAA in serum, and island foxes have a variety of chronic inflammatory diseases that may lead to elevated SAA levels. We found that conformationally sensitive amyloid binding probes known as luminescent conjugated polymers bind the island fox SAA amyloid and emit different spectra within different microanatomical locations in the kidney, suggesting there may be conformational or compositional differences in amyloid deposits.

A Comparison of Elevated Blood Parameter Values in a Population of Thoroughbred Racehorses

In racing Thoroughbred horses, blood cell counts and key biochemistry parameters are used to monitor horse health during training. The most common measure is total white blood cell (WBC) count, usually coupled with estimates of the relative abundance of the five main types of WBC. However, WBC can go down and up when challenged, making interpretation difficult. In contrast, a large majority of health issues that impact training should trigger an inflammatory response. In this study, we test the potential for two inflammatory biomarkers, fibrinogen and serum amyloid A (SAA), to provide more reliable indicators of health issues across a large sample of horses in training. We find that although WBC and other cell counts are generally correlated with each other and other biochemistry parameters across their full range of values, fibrinogen and SAA exhibit the greatest concordance among the top 15% of values. Moreover, horses with the top WBC values do not overlap significantly with those having the top fibrinogen and SAA values. Because most horses are healthy, these patterns suggest that natural variation in cell counts and biochemistry largely occlude values that might indicate health issues. In contrast, the subset of unusual horses with elevated levels of both fibrinogen and SAA are strongly suggestive of the expected handful of animals with minor, undetected issues. We conclude that fibrinogen and SAA have excellent potential as biomarkers and are likely to be more informative about conditions relevant to horses in training compared with the widely used WBC.

Serum amyloid A, phospholipase A2-IIA and C-reactive protein as inflammatory biomarkers for prostate diseases

Serum amyloid A (SAA), secreted group IIA phospholipase A₂ (sPLA₂-IIA), and C-reactive protein (CRP) are acute-phase proteins whose serum concentrations increase not only during inflammatory disorders, but also in the course of malignant diseases. In this study we analyzed serum levels of these inflammatory markers along with prostate-specific antigens (PSA) in patients with benign prostatic hyperplasia (BPH, n = 55), localized prostate cancers (PCa, n = 55), and metastatic prostate cancers (mPCa, n = 27) using immunological assays. We found that in comparison to healthy individuals (n = 55), patients with BPH, PCa and mPCa have elevated serum levels of SAA, sPLA₂-IIA, and CRP, in addition to elevated levels of PSA. Significant differences with respect to inflammatory biomarkers were found between localized and metastatic PCa (p < 0.001), suggesting a prognostic value of these parameters. In addition, serum concentrations of SAA and sPLA₂-IIA positively correlate with CRP in BPH patients (p < 0.05) and in patients with PCa and mPCa (p < 0.001), but not with PSA levels, Gleason score, or tumor stage, emphasizing a role of SAA and sPLA₂-IIA as circulating biomarkers of inflammation rather than of neoplastic transformation. In contrast to PSA, which differed significantly between BPH and localized PCa patients (p < 0.01), such a difference was not found for SAA, sPLA₂-IIA, and CRP. In order to elucidate whether the elevated levels of SAA and sPLA₂-IIA can be caused by cancer cell-associated synthesis, in vitro studies were performed. These analyses demonstrated the expression of SAA and sPLA₂-IIA in LNCaP and PC-3 prostate cell lines, which can be further upregulated by pro-inflammatory cytokines in a cell type-dependent manner. This might suggest that, in addition to the hepatic origin, SAA and sPLA₂-IIA can also be synthesized and secreted by prostatic cancer tissue itself. The results of the present study emphasize the utility of SAA, sPLA₂-IIA, and CRP as circulating biomarkers of inflammation during BPH development and PCa progression.

Serum Amyloid A: Expression Throughout Human Ovarian Folliculogenesis and Levels in Follicular Fluid of Women Undergoing Controlled Ovarian Stimulation

Serum amyloid A (SAA) is an acute phase protein expressed primarily in the liver in response to various injuries and inflammatory stimuli and is recognized as a modulator of inflammation. Ovarian reproductive functions including folliculogenesis and ovulation use inflammatory processes; thus, studying SAA in this context is of interest. We investigated the expression and localization of SAA in ovarian developing follicles and its levels in follicular fluids. Nonradioactive in situ hybridization and immunohistochemical staining were applied on ovarian paraffin tissue sections. ELISA and RT-PCR were applied on follicular aspirates and blood samples from women undergoing controlled ovarian stimulation for in vitro fertilization. Expression of SAA mRNA and protein was found in follicular cells at all stages of follicular development, from primordial and primary follicles through antral follicles and corpora lutea. Expression was observed in granulosa, theca and luteal cells, and oocytes. Expression of SAA was also found in granulosa cells recovered from follicular aspirates. The SAA protein was detected in follicular fluids. Its levels were somewhat lower than in peripheral blood with strong correlation between the two compartments and with significant correlation with patient's body mass index. High follicular fluid SAA levels were associated with reduced pregnancy rate. SAA is locally produced in ovarian developing follicles and is a constituent of follicular fluids, suggesting its role within the follicular environment. Elevated follicular SAA levels are associated with decreased pregnancy rate and may signify lower reproductive performance.