Serum amyloid A1 induced dysfunction of airway macrophages via CD36 pathway in allergic airway inflammation.

Previous studies showed that serum amyloid A (SAA) and macrophages were associated with allergic airway inflammation. However, the interaction between SAA1 and macrophages in allergic airway inflammation remains to be further elucidated. In this study, the levels of SAA1 were measured in nasal tissues from patients with eosinophilic chronic rhinosinusitis with nasal polyps (CRSwNP), house dust mite (HDM)-treated BEAS-2B cells and the tissues of mice of HDM-induced allergic airway inflammation. Human monocytes-derived macrophages and mouse bone marrow-derived macrophages (BMDMs) were exposed to SAA1, and CCL17 and the other M1/M2-related factors were evaluated using RT-PCR and/or ELISA. To test the effects of SAA1-treated BMDMs on chemotaxis and differentiation of CD4+ T cells, number of migrated cells and the levels of Th1 and Th2 were measured using flow cytometry. SAA1 receptors were examined in BMDMs and lung macrophages of model mice. CD36 neutralizing antibody was applied to explore the mechanisms of SAA1 in regulating BMDMs using RT-PCR and/or ELISA. We found that SAA1 was expressed in epithelial cells, and was increased in the nasal tissues of patients with eosinophilic CRSwNP and HDM-treated BEAS-2B- cells as well as the bronchoalveolar lavage fluid and lung tissues of mice exposed to HDM. We also found that the level of CCL17 was increased in M2 macrophages, more CD4+ T cells were recruited and proportion of Th2 was increased after the treatment of SAA1. The treatment of CD36 neutralizing antibody decreased CCL17 level in SAA1-treated M2 BMDMs. In summary, our results showed that SAA1 was increased in allergic airway inflammation, and the administration of SAA1 upregulated the expression of CCL17 in M2 macrophages via CD36 and promoted the chemotaxis of CD4+ T cells and differentiation of Th2. It may provide a new therapeutic strategy that could mediate allergic airway inflammation via suppressing SAA1 to reduce recruitment of CD4+ T cells and activation of Th2.

Key charged residues influence the amyloidogenic propensity of the helix-1 region of serum amyloid A.

Increased plasma levels of serum amyloid A (SAA), an acute-phase protein that is secreted in response to inflammation, may lead to the accumulation of amyloid in various organs thereby obstructing their functions. Severe cases can lead to a systemic disorder called AA amyloidosis. Previous studies suggest that the N-terminal helix is the most amyloidogenic region of SAA. Moreover, computational studies implicated a significant role for Arg-1 and the residue-specific interactions formed during the fibrillization process. With a focus on the N-terminal region of helix-1, SAA1-13, mutational analysis was employed to interrogate the roles of the amino acid residues, Arg-1, Ser-5, Glu-9, and Asp-12. The truncated SAA1-13 fragment was systematically modified by substituting the key residues with alanine or uncharged but structurally similar amino acids. We monitored the changes in the amyloidogenic propensities, associated conformational markers, and morphology of the amyloids resulting from the mutation of SAA1-13. Mutating out Arg-1 resulted in much reduced aggregation propensity and a lack of detectable ß-structures alluding to the importance of salt-bridge interactions involving Arg-1. Our data revealed that by systematically mutating the key amino acid residues, we can modulate the amyloidogenic propensity and alter the time-dependent conformational variation of the peptide. When the behaviors of each mutant peptide were analyzed, they provided evidence consistent with the aggregation pathway predicted by MD simulation studies. Here, we detail the important temporal molecular interactions formed by Arg-1 with Ser-5, Glu-9, and Asp-12 and discuss its mechanistic implications on the self-assembly of the helix-1 region of SAA.

Diagnostic significance of serum levels of serum amyloid A, procalcitonin, and high-mobility group box 1 in identifying necrotising enterocolitis in newborns.

BACKGROUND: Necrotising enterocolitis (NEC) is a critical gastrointestinal emergency affecting premature and low-birth-weight neonates. Serum amyloid A (SAA), procalcitonin (PCT), and high-mobility group box 1 (HMGB1) have emerged as potential biomarkers for NEC due to their roles in inflammatory response, tissue damage, and immune regulation. AIM: To evaluate the diagnostic value of SAA, PCT, and HMGB1 in the context of NEC in newborns. METHODS: The study retrospectively analysed the clinical data of 48 newborns diagnosed with NEC and 50 healthy newborns admitted to the hospital. Clinical, radiological, and laboratory findings, including serum SAA, PCT, and HMGB1 Levels, were collected, and specific detection methods were used. The diagnostic value of the biomarkers was evaluated through statistical analysis, which was performed using chi-square test, t-test, correlation analysis, and receiver operating characteristic (ROC) analysis. RESULTS: The study demonstrated significantly elevated levels of serum SAA, PCT, and HMGB1 Levels in newborns diagnosed with NEC compared with healthy controls. The correlation analysis indicated strong positive correlations among serum SAA, PCT, and HMGB1 Levels and the presence of NEC. ROC analysis revealed promising sensitivity and specificity for serum SAA, PCT, and HMGB1 Levels as potential diagnostic markers. The combined model of the three biomarkers demonstrating an extremely high area under the curve (0.908). CONCLUSION: The diagnostic value of serum SAA, PCT, and HMGB1 Levels in NEC was highlighted. These biomarkers potentially improve the early detection, risk stratification, and clinical management of critical conditions. The findings suggest that these biomarkers may aid in timely intervention and the enhancement of outcomes for neonates affected by NEC.

[Diagnostic Value of Interleukin 6, Interleukin 12P70, Serum Amyloid A, and Procalcitonin for Rheumatoid Arthritis and Their Relationship With the Disease Activity]. / ç™½ä»‹ç´ 6ã€ç™½ä»‹ç´ 12P70ã€è¡€æ¸ æ·€ç²‰æ ·è›‹ç™½é ¶Aå’Œé™é’™ç´ åŽŸå¯¹ç±»é£Žæ¹¿å ³èŠ‚ç‚Žçš„è¯Šæ–­ä»·å€¼åŠä¸Žç–¾ç— æ´»åŠ¨åº¦çš„å ³ç³».

Objective: To observe the diagnostic value of four serum inflammatory biomarkers, including interleukin 6 (IL-6), interleukin 12P70 (IL-12P70), serum amyloid A (SAA), and procalcitonin (PCT), in rheumatoid arthritis (RA) and to analyze their relationship with the disease activity. Methods: The study included 60 RA patients admitted to the Department of Rheumatology at Anhui Provincial Hospital of Traditional Chinese Medicine between December 2022 and December 2023. Thirty healthy individuals from the hospital's physical examination center served as the control group. Serum levels of IL-6 and IL-12P70 were detected using flow cytometry. SAA levels were determined by immunoturbidimetry, and PCT levels were assessed by chemiluminescence. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), rheumatoid factor (RF), and anticyclic citrullinated peptide (ACCP) were detected using an automated biochemical analyzer. The 28-joint disease activity scores (DAS28-ESR) based on ESR were observed. Statistical analysis included t-tests, rank-sum tests, and Kruskal-Wallis H tests to compare the expression differences of the biomarkers among different groups. The diagnostic value of these biomarkers for RA was analyzed by ROC curve analysis. Spearman correlation analysis was performed to assess the relationships between the four inflammatory biomarkers and CRP, ESR, RF, ACCP, and DAS28-ESR. Results: 1) The expression levels of SAA, IL-6, and IL-12P70 in the RA group were significantly higher than those in the control group (P<0.01). 2) ROC curve analysis showed that the area under the curve (AUC) for PCT was 0.611 (95% confidence interval [CI]: 0.488-0.735, P>0.05), for SAA, it was 0.819 (95% CI: 0.733-0.906, P<0.01), for IL-6, it was 0.875 (95% CI: 0.803-0.946, P<0.01), and for IL-12P70, it was 0.832 (95% CI: 0.746-0.917, P<0.01). The combined index of IL-6, IL-12P70, SAA, and PCT had an AUC of 0.973 (95% CI: 0.942-1.000, P<0.01). This indicates that the four inflammatory biomarkers can assist in the diagnosis of rheumatoid arthritis. 3) The expression levels of PCT and SAA varied significantly among the high, moderate, and low activity RA groups (P<0.01). 4) In RA patients, CRP was positively correlated with SAA (rs =0.75, P<0.01), and IL-6 (rs =0.52, P<0.01). ESR was positively correlated with SAA (rs =0.36, P<0.01). DAS28-ESR was positively correlated with PCT (rs =0.34, P=0.01), SAA (rs =0.51, P<0.01) and IL-6 (rs =0.33, P=0.01). Conclusion: The four inflammatory biomarkers (PCT, SAA, IL-6, and IL-12P70) are closely related to rheumatoid arthritis disease activity and can serve as serum indicators to assist in the diagnosis and assessment of RA.

Differences in HDL Remodeling during Healthy Pregnancy and Pregnancy with Cardiometabolic Complications.

This study investigated the longitudinal trajectory of changes in antioxidative and anti-inflammatory high-density lipoprotein (HDL) components during healthy pregnancy and pregnancy with cardiometabolic complications. We recruited and longitudinally followed 84 women with healthy pregnancies and 46 pregnant women who developed cardiometabolic pregnancy complications (gestational diabetes mellitus and hypertensive disorders of pregnancy). Their general lipid profiles, oxidative stress status, inflammatory status, and antioxidative and anti-inflammatory HDL components were analyzed. The results of our study confirmed the expected trajectory for the routine lipid parameters. Our study results indicate more intensive oxidative stress and a higher level of inflammation in the group with complications compared with the control group. Sphingosine-1-phosphate (S1P) was significantly lower in the first trimester in the group with complications compared with the control group (p < 0.05). We did not find significant differences in the apolipoprotein A1 (Apo A1) concentrations in the first trimester between the control group and the group with complications, but in the second and third trimesters, the group with complications had significantly higher concentrations (p < 0.001, p < 0.05, respectively). The S1P, paraoxonase 1 (PON1), and serum amyloid A (SAA) concentrations were significantly lower in the group with complications in the first trimester. During the second trimester, only the SAA concentrations were identified as significantly lower in the group with complications compared with the control group, while in the third trimester, the PON1, apolipoprotein M (Apo M), and SAA concentrations were all significantly lower in the group with complications. Through a multivariate binary logistic regression analysis, the S1P concentration in the first trimester was distinguished as an HDL-associated marker independently associated with cardiometabolic pregnancy complications. In conclusion, our study results showed that HDL remodeling differs between healthy pregnancies and pregnancies with maternal cardiometabolic complications, with changed HDL composition and functionality consequently impacting its biological functionality in the latter case.

Role of SAA1 in endometrial extracellular matrix remodeling in polycystic ovary syndrome: implication for pregnancy loss.

CONTEXT: Abnormal endometrial extracellular matrix (ECM) remodeling compromises endometrial receptivity and diminishes the probability of a successful live birth. Serum amyloid A1 (SAA1), a modulator of inflammation, is elevated in the circulation of polycystic ovary syndrome (PCOS) patients and involved in ECM remodeling during tissue repair. However, the specific role of SAA1 in endometrial ECM remodeling and subsequent risk of pregnancy loss in PCOS patients remains unclear. OBJECTIVE: To examine the role and underlying mechanism of SAA1 in ECM remodeling in the endometrium of PCOS patients. DESIGN: Serum samples from PCOS and control patients were utilized to investigate the relationship between the abundance of SAA1 and pregnancy loss. Human endometrial tissues and primary human endometrial stromal cells were used to examine the role and underlying mechanism of SAA1 in ECM remodeling. RESULTS: Serum SAA1 concentration was elevated and could serve as an independent risk of pregnancy loss in PCOS patients. Increased SAA1 abundance was also observed in endometrium obtained from these patients. Further mechanistic studies showed that SAA1 stimulated collagen I chains synthesis (COL1A1 and COL1A2) in endometrial stromal cells, suggesting excessive SAA1 may contribute to endometrial ECM remodeling, resulting in a non-supportive environment for ongoing pregnancy. This effect was abolished by either a toll-like receptors 2/4 antagonist or a nuclear factor κB inhibitor. CONCLUSIONS: The locally elevated levels of SAA1 in endometrium contribute to ECM over-deposition by inducing collagen I synthesis in PCOS patients, which may hamper embryo implantation and increase the risk of pregnancy loss. These observations highlight the crucial role of heightened SAA1 in orchestrating endometrial dysfunction and shed light on potential therapeutic avenues for improving reproductive outcomes in PCOS patients.

The ASC inflammasome adapter governs SAA-derived protein aggregation in inflammatory amyloidosis.

Extracellularly released molecular inflammasome assemblies -ASC specks- cross-seed Aß amyloid in Alzheimer's disease. Here we show that ASC governs the extent of inflammation-induced amyloid A (AA) amyloidosis, a systemic disease caused by the aggregation and peripheral deposition of the acute-phase reactant serum amyloid A (SAA) in chronic inflammatory conditions. Using super-resolution microscopy, we found that ASC colocalized tightly with SAA in human AA amyloidosis. Recombinant ASC specks accelerated SAA fibril formation and mass spectrometry after limited proteolysis showed that ASC interacts with SAA via its pyrin domain (PYD). In a murine model of inflammatory AA amyloidosis, splenic amyloid load was conspicuously decreased in Pycard-/- mice which lack ASC. Treatment with anti-ASCPYD antibodies decreased amyloid loads in wild-type mice suffering from AA amyloidosis. The prevalence of natural anti-ASC IgG (-logEC50 ≥ 2) in 19,334 hospital patients was <0.01%, suggesting that anti-ASC antibody treatment modalities would not be confounded by natural autoimmunity. These findings expand the role played by ASC and IL-1 independent inflammasome employments to extraneural proteinopathies and suggest that anti-ASC immunotherapy may contribute to resolving such diseases.

Plasma concentration of serum amyloid A and lipopolysaccharide binding protein in horses with laminitis resulted from hindgut acidosis.

Many studies have shown a strong correlation between Hindgut Acidosis (HGA) and the occurrence of laminitis in horses; therefore, the early diagnosis of HGA is essential. In this study, we investigated changes in the plasma concentrations of lipopolysaccharide-binding protein (LBP) and serum amyloid A (SAA) as inflammatory markers in horses with laminitis. Sixteen healthy male Arabian horses that had cecal cannulation without visible laminitis or general symptoms were randomly divided into two groups. The horses were fed two different diets in a forage-to-concentrate ratio. Blood samples were collected on Days 1, 10, and 20. The primary objective of this study was to analyze plasma levels of LBP and SAA. Cecal specimens were obtained from each equine subject on three designated days: days 1, 10, and 20. The second objective was to assess the levels of pH and volatile fatty acids (VFA) in the samples. Throughout the study period, horses fed a high-concentrate diet exhibited a significantly elevated average lameness grade on days 10 and 20 compared to the initial stage (P < 0.001). On day 20, a significant increase in the concentration of SAA was observed in horses fed a high-concentrate diet, in contrast to the initial stage of the study. LBP levels in the plasma were significantly elevated on days 10 and 20 in horses fed a high-concentrate diet. Based on our findings, it is recommended that the evaluation of plasma LBP concentrations is more effective than SAA for the early identification of HGA in horses fed a high-grain diet.

New Regulatory roles for Human Serum Amyloid A.

The current study illuminates the multifaceted role of Serum Amyloid A (SAA), an essential acute-phase protein implicated in diverse biological realms, encompassing inflammation, oncogenesis, and stress modulation. With a focus on delineating the intricate protein-protein interactions orchestrated by SAA, this investigation unravels its diverse functions within the human physiological landscape. Utilizing the HepG2 cell line, renowned for its proficiency in facilitating SAA overexpression, we meticulously generated protein extracts after inducing SAA hyperexpression. Integrating Co-Immunoprecipitation techniques with Liquid Chromatography-Tandem Mass Spectrometry (LC/MS/MS) enabled discernment and characterization of the protein complexes intricately associated with SAA. Our data elucidates a pronounced upregulation in SAA expression levels within induced samples compared to controls, substantiating its pivotal role among inflammatory cascades. Specifically, LC/MS/MS profiling delineated interactions with nine distinct proteins, encompassing pivotal players in actin dynamics, neuronal morphogenesis, lipid homeostasis, and immunomodulation. Furthermore, this investigation underscores the plausible ramifications of these molecular interactions in pathologies, including Alzheimer's disease, oncological manifestations, and rheumatoid arthritis. Through comprehensive analyses, this investigation sheds light on the intricate roles of SAA and provides a foundation for future therapeutic modalities targeting SAA pathologies.

Cyclic Nitroxide 4-Methoxy-Tempo May Decrease Serum Amyloid A-Mediated Renal Fibrosis and Reorganise Collagen Networks in Aortic Plaque.

Acute-phase serum amyloid A (SAA) can disrupt vascular homeostasis and is elevated in subjects with diabetes, cardiovascular disease, and rheumatoid arthritis. Cyclic nitroxides (e.g., Tempo) are a class of piperidines that inhibit oxidative stress and inflammation. This study examined whether 4-methoxy-Tempo (4-MetT) inhibits SAA-mediated vascular and renal dysfunction. Acetylcholine-mediated vascular relaxation and aortic guanosine-3',5'-cyclic monophosphate (cGMP) levels both diminished in the presence of SAA. 4-MetT dose-dependently restored vascular function with corresponding increases in cGMP. Next, male ApoE-deficient mice were administered a vehicle (control, 100 µL PBS) or recombinant SAA (100 µL, 120 µg/mL) ± 4-MetT (at 15 mg/kg body weight via i.p. injection) with the nitroxide administered before (prophylaxis) or after (therapeutic) SAA. Kidney and hearts were harvested at 4 or 16 weeks post SAA administration. Renal inflammation increased 4 weeks after SAA treatment, as judged by the upregulation of IFN-γ and concomitant increases in iNOS, p38MAPK, and matrix metalloproteinase (MMP) activities and increased renal fibrosis (Picrosirius red staining) in the same kidneys. Aortic root lesions assessed at 16 weeks revealed that SAA enhanced lesion size (vs. control; p < 0.05), with plaque presenting with a diffuse fibrous cap (compared to the corresponding aortic root from control and 4-MetT groups). The extent of renal dysfunction and aortic lesion size was largely unchanged in 4-MetT-supplemented mice, although renal fibrosis diminished at 16 weeks, and aortic lesions presented with redistributed collagen networks. These outcomes indicate that SAA stimulates renal dysfunction through promoting the IFN-γ-iNOS-p38MAPK axis, manifesting as renal damage and enhanced atherosclerotic lesions, while supplementation with 4-MetT only affected some of these pathological changes.

Serum amyloid A increases following routine vaccination of healthy adult horses.

OBJECTIVES: To measure the effect of routine vaccination on serum amyloid A (SAA) concentration in apparently healthy horses. We hypothesized that routine vaccination would increase SAA in healthy horses. ANIMALS: 21 apparently healthy client-owned horses and 15 Kansas State University College of Veterinary Medicine-owned horses. METHODS: In experiment 1 (n = 8 horses), a blinded, randomized, prospective, crossover study was performed. Horses were either vaccinated (rabies, tetanus, West Nile, Eastern and Western equine encephalomyelitis, equine herpesvirus-1/-4, influenza) or administered saline, and SAA was measured at 6, 12, and 24 hours and daily until day 10 with a commercial lateral-flow immunoassay. In experiment 2 (n = 28 horses), a prospective, observational study measured SAA after vaccination at 12 and 24 hours and daily until day 10. A linear mixed-effect model with repeated measures over time blocked by horse tested the effect of treatment on SAA. A repeated-measures correlation tested the correlation between SAA and temperature. RESULTS: Over time, vaccinated horses had increased model-adjusted SAA compared to unvaccinated horses without clinical evidence of adverse reaction (P < .01). In experiment 1, the model-adjusted SAA after vaccination peaked on day 2 (median, 1,872 µg/mL; IQR, 1,220.8 to 2,402.5 µg/mL) and returned to normal (< 20 µg/mL) by day 9 (median, 6 µg/mL; IQR, 0.8 to 23.5 µg/mL) after vaccination. In experiment 2, vaccinated horses had increased SAA over time; temperature and SAA were not correlated (P = .78). CLINICAL RELEVANCE: Results of this study indicated that routine vaccination results in increased SAA concentration and provided evidence for a period of convalescence following vaccination. Measuring SAA for 10 days following vaccination cannot be used as an indicator of illness.

Systemic inflammation biomarkers during angioedema attacks in hereditary angioedema.

Background: Hereditary angioedema (HAE) is a rare disease characterized by localized and self-limited angioedema (AE) attacks. A local increase of bradykinin (BK) mediates AE attacks in HAE, however the role of inflammation in HAE has been poorly explored We aim to analyze the role of inflammatory mediators in HAE patients during AE attacks. Methods: Patients with a confirmed HAE diagnosis due to C1 inhibitor deficiency (HAE-C1INH) or patients F12 gene mutations (HAE-FXII) attending to our outpatient clinic between November-2019 and May-2022 were included. Demographic and clinical characteristics were analyzed. Blood samples were collected both during symptom-free periods (baseline) and during HAE attacks, and acute phase reactants (APR), such as serum amyloid A (SAA), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), D-Dimer and white blood cells were measured. Results: Seventy-eight patients were enrolled in the study, with a predominant representation of women (76%, n=59), and a mean age of 47.8 years (range 6-88). Among them, 67% (n=52) of patients had HAE-C1INH (46 classified as type 1 and 6 as type 2) while 33% (n=26) had HAE-FXII. During attack-free periods, the majority of patients exhibited normal levels of SAA, ESR, D-dimer, ACE and WCC. However, in a subset of patients (16% for SAA, 18% for ESR, and 14.5% for D-dimer), elevations were noted at baseline. Importantly, during HAE attacks, significant increases were observed in SAA in 88% of patients (p< 0.0001 vs. baseline), in ESR in 65% (p= 0.003 vs. baseline) and D-dimer in 71% (p=0.001 vs. baseline) of the patients. A comparison between baseline and acute attack levels in 17 patients revealed significant differences in SAA AA (p<0. 0001), ESR (p<0.0001) and D-dimer (p= 0.004). No significant differences were observed in CRP (p=0.7), ACE (p=0.67) and WCC (p=0.54). These findings remained consistent regardless of HAE type, disease activity or location of angioedema. Conclusion: The systemic increase in APR observed during HAE attacks suggests that inflammation extends beyond the localized edematous area. This finding underscores the potential involvement of inflammatory pathways in HAE and highlights the need for further investigation into their role in the pathophysiology of HAE.

Association of results of the glutaraldehyde coagulation test with plasma acute phase protein concentrations and hematologic findings in hospitalized cows.

Introduction: The glutaraldehyde test (GAT) allows for animal-side semi-quantitative estimation of fibrinogen and gamma-globulin concentrations in blood samples of adult cattle and therefore detection of inflammatory disease conditions. However, the test has potential limitations, especially due to the latency period until sufficiently high fibrinogen and/or gamma-globulin concentrations are reached. The aim of the present study was therefore to assess the association between results of GAT with other inflammatory markers including hematologic variables, fibrinogen, plasma haptoglobin and serum amyloid A (SAA) concentrations. Methods: For the purpose of this prospective observational study, a convenience sample of 202 cows with a broad range of inflammatory and non-inflammatory clinical conditions was included. The GAT was run on EDTA blood, fibrinogen was measured using the Clauss and the heat precipitation method, and commercially available ELISA tests were used for determination of plasma haptoglobin and SAA concentrations. Results: Shortened GAT coagulation times were more closely correlated to serum globulin (rs = -0.72) than to plasma fibrinogen concentrations measured with the heat precipitation (rs = -0.64) and the Clauss method (rs = -0.70). Cows with a markedly (≤3 min) or moderately (4-6 min) shortened coagulation time had higher (p < 0.001) plasma haptoglobin and SAA concentrations than cows with a negative test result. Total leukocyte, monocyte and neutrophil concentrations did not differ significantly between groups. An identified cut-off for the GAT coagulation time of ≤14 min had a sensitivity and specificity of 54.4 and 100%, respectively, for the prediction of an inflammatory state based on clinical findings and/or increased plasma haptoglobin or SAA concentrations. Discussion: In conclusion, this study demonstrates considerable diagnostic agreement between positive GAT results and increased plasma concentrations of haptoglobin and SAA. Despite high specificity, the test lacks sensitivity in case of acute inflammatory conditions indicating that plasma acute phase protein concentrations and hematologic findings can provide additional diagnostic information if the GAT is negative.

The potential role of serum amyloid A as biomarker of rheumatic diseases: a systematic review and meta-analysis.

The identification of novel, robust biomarkers for the diagnosis of rheumatic diseases (RDs) and the presence of active disease might facilitate early treatment and the achievement of favourable long-term outcomes. We conducted a systematic review and meta-analysis of studies investigating the acute phase reactant, serum amyloid A (SAA), in RD patients and healthy controls to appraise its potential as diagnostic biomarker. We searched PubMed, Scopus, and Web of Science from inception to 10 April 2024 for relevant studies. We evaluated the risk of bias and the certainty of evidence using the JBI Critical Appraisal Checklist and GRADE, respectively (PROSPERO registration number: CRD42024537418). In 32 studies selected for analysis, SAA concentrations were significantly higher in RD patients compared to controls (SMD = 1.61, 95% CI 1.24-1.98, p < 0.001) and in RD patients with active disease compared to those in remission (SMD = 2.17, 95% CI 1.21-3.13, p < 0.001). Summary receiving characteristics curve analysis showed a good diagnostic accuracy of SAA for the presence of RDs (area under the curve = 0.81, 95% CI 0.78-0.84). The effect size of the differences in SAA concentrations between RD patients and controls was significantly associated with sex, body mass index, type of RD, and study country. Pending the conduct of prospective studies in different types of RDs, the results of this systematic review and meta-analysis suggest that SAA is a promising biomarker for the diagnosis of RDs and active disease.

Assessment of IBD disease activity by Interleukin-6 and serum amyloid A in relation with fecal calprotectin and endoscopic indices.

BACKGROUND AND STUDY AIMS: Close monitoring of disease activity in IBD patients is essential to avoid long term complications. Although endoscopic assessment is the ideal monitoring tool, the usage of noninvasive biomarkers is more practical and patient friendly. We aimed to study the performance of Interleukin-6(IL-6) and Serum Amyloid A(SAA) as serum biomarkers in assessment of the disease activity of IBD patients in correlation to C-reactive protein (CRP), Fecal Calprotectin (FC) and endoscopic indices. METHODS: 83 IBD (26 CD and 57 UC) patients on stable treatment regimen were recruited. Serum markers included CRP, CBC, IL-6, SAA were analyzed, together with FC. These markers were compared with the endoscopic and clinical disease parameters. Harvey-Bradshaw Index (HBI) and the Simple Clinical Colitis Activity Index (SCCAI) were used to assess clinical activity in CD and UC patients, respectively. Endoscopic activity was recorded using the Simple Endoscopic Score (SES) for Crohn's disease or the Mayo Endoscopic Score (MES) for ulcerative colitis. RESULTS: In prediction of disease activity, IL-6, SAA and CRP demonstrated good area under receiver operating characteristics (AUC) (>0.7), with FC being the best (0.94) for endoscopically active disease (P < 0.01). Combining FC and IL-6 or SAA improved its discriminative accuracy with an AUC (∼0.96). CONCLUSIONS: FC most accurately predicts endoscopic disease activity in IBD patients, in comparison to other studied serological biomarkers. The serum IL-6 and SAA are potential predictors of endoscopic disease activity, and they might be valuable for assessment of disease activity. Finally, a composite score of FC and SAA or IL-6 can increased its diagnostic accuracy.

Comparison of polyclonal and monoclonal antibody assays for serum amyloid A in cats: a study based on an automated turbidimetric immunoassay in a primary care veterinary hospital.

OBJECTIVE: Comparing the utility of the anti-human serum amyloid A (SAA)-specific monoclonal and polyclonal antibodies assays (LZ-SAA) with the pure monoclonal anti-human antibody assays (VET-SAA) during clinical practice in primary care hospital populations by measuring SAA measurement in healthy and diseased domestic cats. ANIMALS: 52 healthy and 185 diseased client-owned cats. METHODS: SAA concentration was measured using different LZ-SAA and VET-SAA measurements for healthy and various diseased cats. Sensitivity, specificity, and accuracy were calculated for each disease. RESULTS: VET-SAA has higher sensitivity than LZ-SAA for the most common diseases presenting to primary care veterinary hospitals, including chronic kidney disease, tumors, and gingivostomatitis. Our results reveal the capability of detecting low SAA concentrations in healthy and diseased cats using VET-SAA in contrast to LZ-SAA, which found elevations of SAA concentrations only in diseased cats. CLINICAL RELEVANCE: Our findings indicate that switching to the new VET-SAA instead of the conventional LZ-SAA will likely enhance the diagnostic performance in primary care veterinary hospitals.

Serum Amyloid A and Haptoglobin concentrations in calves at first event of respiratory disease were not associated with subsequent risk of respiratory disease during the preweaning period.

Bovine respiratory disease (BRD) causes decreased welfare and production losses and is a major reason for use of antimicrobials in dairy calves. Inflammatory markers released into the blood stream during BRD include acute phase proteins such as Serum Amyloid A (SAA) and Haptoglobin (Hp). This longitudinal observational study aimed to investigate whether the serum concentrations of SAA and Hp measured on the day of a detected mild clinical event of BRD, were associated the odds of developing recurrent BRD events requiring additional treatments in up to a 46-day follow-up period after the first event. A total of 65 preweaned dairy calves were observed for 46 days each in one Danish dairy herd. They were enrolled in this study in the age between 17 and 24 days of age and were followed for the following 46 days in total in which the calves potentially could develop an event of BRD. The calves were clinically assessed every other day using a Visual Analogue Scale (VAS), where a mild BRD event was defined as a calf that deviated from a normal and non-affected calf. The clinical signs included that the calf was less interested in its surroundings, slightly depressed, less bright, alert, and responsive with less clear eyes and using longer time to get up. The calf could have scruffy hair coat and drooping ears. Blood samples were collected on the day of the first mild BRD event that was only treated with a non-steroidal anti-inflammatory drug. A logistic regression model was performed to detect associations between having recurrent events of BRD and VAS, serum SAA and Hp concentrations at the day of the first BRD event and the follow-up period after the BRD event. Only the follow-up period after the first BRD event had a significant association with the odds ratio of having recurrent events of BRD of 2.3 for a 10-day difference in follow-up time after the BRD event.

Changes in plasma metabolite concentrations and enzyme activities in aging riding horses.

In older horses, basal metabolic rate decreases, and plasma metabolite and hormone concentrations related to energy metabolism change. The occurrence of age-related diseases, which increases in old animals, may enhance inflammatory reactivity (inflammaging). Finding the appropriate treatment for inflammaging at an early stage may prevent various age-related diseases. Changes in metabolite and hormone concentrations and enzyme activities involved in energy metabolism in the plasma of clinically healthy riding horses of various ages were measured to identify biomarkers of inflammaging (persistent low-grade inflammation that occurs with aging). All horses were clinically healthy, and their body condition scores (BCSs) were 4 or 5 (9-point scale). Plasma triglyceride (TG), total cholesterol (T-Cho), blood urea nitrogen (BUN), insulin concentrations, malondialdehyde (MDA), and serum amyloid A (SAA) concentrations generally increased with age. Adiponectin concentrations, plasma superoxide dismutase (SOD), and leukocyte AMP-activated protein kinase (AMPK) activities decreased, while plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), and glutathione peroxidase (GPx) remained unchanged as horses aged. Although riding horses that partake in continuous exercise seems to be less likely to develop inflammaging, horses over 17 years of age tend to show proinflammatory signs with disordered lipid metabolism. In riding horses, SAA, in combination with other markers, may be a useful biomarker for inflammaging and dysregulated lipid metabolism in aging horses.

Increased serum IL­41 associated with acute exacerbation of chronic obstructive pulmonary disease.

Interleukin (IL)-41 is a novel immunomodulatory cytokine involved in the pathogenesis of several inflammatory and metabolic illnesses. However, it remains unclear how IL-41 contributes to the pathogenesis of chronic obstructive pulmonary disease (COPD). Therefore, the aim of the present study was to explore the correlation between the expression level of IL-41 and acute exacerbation of COPD (AECOPD). In total, 107 patients with COPD and 56 healthy controls were recruited from the First Affiliated Hospital of Ningbo University (Ningbo, China). Serum IL-41, IL-6, and matrix metalloproteinase-2 (MMP-2) levels were evaluated using enzyme-linked immunosorbent assay. Serum amyloid A (SAA) and C-reactive protein (CRP) levels were assessed in the hospital laboratory. The levels of IL-41 were higher in the AECOPD group than in the stable COPD (SCOPD) and control groups (P<0.0001). IL-6, SAA and CRP levels, the percentage of neutrophils, as well as neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios were higher in the AECOPD group than those in the SCOPD and control groups. The smoking index was positively correlated with serum IL-41, CRP and SAA levels. The expression level of IL-41 was correlated with the number of acute exacerbations, severity of the exacerbations, and COPD assessment test scores in the AECOPD group. Examination of the receiver operating characteristic (ROC) curves showed that IL-41, especially when combined with other inflammatory factors, had a specific diagnostic value for AECOPD. According to the ROC curve analysis, the area under the curve (AUC) for IL-41 was 0.742 (P=0.051), and the AUC for IL-41 combined with other inflammatory factors was 0.925 (P=0.030). Increased serum IL-41 levels were associated with AECOPD and may play a role in the monitoring and evaluation of COPD.

MG132 dramatically reduces SAA expression in chicken hepatocellular carcinoma cells at the transcript level independent of its endogenous promoter.

BACKGROUND: MG132, a proteasome inhibitor, is widely used to inhibit nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activity by proteasome-mediated degradation of IκB. It has been marketed as a specific, reversible, cell-permeable and low-cost inhibitor. However, adverse effects of the compound have been reported in the literature. We recently discovered and characterised a point mutation in the acute phase protein serum amyloid A (SAA) in chickens, by overexpressing the protein in chicken hepatocellular carcinoma (LMH) cells. This serine to arginine exchange at amino acid position 90 (SAA.R90S) leads to intra- and extracellular accumulation of SAA, which is surprisingly counteracted by MG132 treatment, independent of SAA's intrinsic promoter. METHODS AND RESULTS: To test, whether low proteasomal degradation of SAA.R90S is responsible for the observed intra- and extracellular SAA accumulation, we intended to inhibit the proteasome in SAA wild type (SAA.WT) overexpressing cells with MG132. However, we observed an unexpected drastic decrease in SAA protein expression at the transcript level. NF-κB gene expression was unchanged by MG132 at the measured time point. CONCLUSIONS: The observed results demonstrate that MG132 inhibits SAA expression at the transcript level, independent of its endogenous promoter. Further, the data might indicate that NF-κB is not involved in the observed MG132-induced inhibition of SAA expression. We, consequently, question in this brief report whether MG132 should truly be categorised as a specific ubiquitin proteasome inhibitor and recommend the usage of alternative compounds.