Serum amyloid A: expression throughout human ovarian folliculogenesis and levels in follicular fluid of women undergoing controlled ovarian stimulation.

BACKGROUND: 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. OBJECTIVES: We investigated the expression and localization of SAA in ovarian developing follicles and its levels in follicular fluids. METHODS AND PARTICIPANTS: 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. RESULTS: 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. CONCLUSIONS: 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.

Expression of serum amyloid a in human ovarian epithelial tumors: implication for a role in ovarian tumorigenesis.

Serum amyloid A (SAA) is an acute phase protein which is expressed primarily in the liver as a part of the systemic response to various injuries and inflammatory stimuli; its expression in ovarian tumors has not been described. Here, we investigated the expression of SAA in human benign and malignant ovarian epithelial tumors. Non-radioactive in situ hybridization applied on ovarian paraffin tissue sections revealed mostly negative SAA mRNA expression in normal surface epithelium. Expression was increased gradually as epithelial cells progressed through benign and borderline adenomas to primary and metastatic adenocarcinomas. Similar expression pattern of the SAA protein was observed by immunohistochemical staining. RT-PCR analysis confirmed the overexpression of the SAA1 and SAA4 genes in ovarian carcinomas compared with normal ovarian tissues. In addition, strong expression of SAA mRNA and protein was found in the ovarian carcinoma cell line OVCAR-3. Finally, patients with ovarian carcinoma had high SAA serum levels, which strongly correlated with high levels of CA-125 and C-reactive protein. Enhanced expression of SAA in ovarian carcinomas may play a role in ovarian tumorigenesis and may have therapeutic application.

Analysis of adenoviral attachment to human platelets.

BACKGROUND: Systemic adenoviral (Ad) vector administration is associated with thrombocytopenia. Recently, Ad interaction with mouse platelets emerged as a key player determining liver uptake and platelet clearance. However, whether Ad can activate platelets is controversial. Thus, in vitro analysis of Ad attachment to platelets is of interest. METHODS: We developed a direct flow cytometry assay to specifically detect Ad particles adherent to human platelets. The method was pre-validated in nucleated cells. Blocking assays were employed to specifically inhibit Ad attachment to platelets. Platelet activation was analyzed using annexin v flow cytometry. RESULTS: We found in vitro that Ad binding to human platelets is synergistically enhanced by the combination of platelet activation by thrombin and MnCl2 supplementation. Of note, Ad binding could activate human platelets. Platelets bound Ad displaying an RGD ligand in the fiber knob more efficiently than unmodified Ad. In contrast to a previous report, CAR expression was not detected on human platelets. Integrins appear to mediate Ad binding to platelets, at least partially. Finally, alphaIIbbeta3-deficient platelets from a patient with Glanzmann thrombasthenia could bind Ad 5-fold more efficiently than normal platelets. CONCLUSION: The flow cytometry methodology developed herein allows the quantitative measurement of Ad attachment to platelets and may provide a useful in vitro approach to investigate Ad interaction with platelets.

The relationship of plasminogen activator inhibitor-1 levels to the ST deviation pattern of acute myocardial infarction.

OBJECTIVES: Myocardial infarction (MI) may be classified as ST elevation MI (STEMI) or non-ST elevation MI (NSTEMI). Procoagulants such as plasminogen activator inhibitor-1 (PAI-1) as well as markers of inflammation such as C-reactive protein (CRP), serum amyloid A (SAA) and interleukin-6 (IL-6) are elevated in acute coronary syndromes. However, no study has examined whether levels of these markers differ in patients with STEMI as opposed to NSTEMI. We sought to determine whether there are differences in plasma levels of PAI-1, CRP, SAA or IL-6 in patients with STEMI compared to patients with NSTEMI. METHODS: Seventy-six consecutive patients presenting with acute MI (37 with STEMI and 39 with NSTEMI) were prospectively enrolled. Blood samples were obtained from patients within 6 h from presentation and plasma PAI-1, CRP, IL-6 and SAA concentrations were measured. RESULTS: Plasma levels of PAI-1 were significantly higher in patients with STEMI compared to NSTEMI: 85.7 +/- 5 vs. 61.3 +/- 5 ng/ml (p < 0.001), while CRP, SAA and IL-6 levels were not significantly different between STEMI and NSTEMI patients. CONCLUSIONS: Higher plasma PAI-1 levels in STEMI patients may contribute to the predilection of these patients to occlusive thrombi and STEMI.

Serum amyloid A enhances plasminogen activation: implication for a role in colon cancer.

We have recently reported that the acute phase protein serum amyloid A (SAA), is locally and differentially expressed in neoplastic tissues of human colon. In the present study, we demonstrate that SAA enhances the plasminogen activation (PA)-activity of HT-29 colon cancer cell line. Cell-associated PA-activity was measured following the plasminogen-dependent ability of the cells to cleave the chromogenic substrate S-2251. The SAA-enhanced PA-activity was inhibited by anti-SAA antibodies. These antibodies also decreased the basal PA-activity of HT-29 cells and neutralized their cytokines (Interleukin-1beta+Interleukin-6)-enhanced PA-activity. Using specific chromogenic substrates and the fibrin clot-lysis assay, we found that SAA enhances also the PA-activity mediated by purified urokinase- and tissue-type plasminogen activators. Together, the data indicate that SAA enhances plasminogen activation and suggest its possible role in plasmin(ogen)-mediated colon cancer progression.

Expression of serum amyloid A, in normal, dysplastic, and neoplastic human colonic mucosa: implication for a role in colonic tumorigenesis.

Serum amyloid A (SAA) is an acute phase reactant, whose level in the blood is elevated in response to trauma, infection, inflammation, and neoplasia. Elevated levels of SAA in the serum of cancer patients were suggested to be of liver origin rather than a tumor cell product. The role of SAA in human malignancies has not been elucidated. We investigated the expression of SAA at various stages of human colon carcinoma progression. Nonradioactive in situ hybridization applied on paraffin tissue sections from 26 colon cancer patients revealed barely detected SAA mRNA expression in normal looking colonic epithelium. Expression was increased gradually as epithelial cells progressed through dysplasia to neoplasia. Deeply invading colon carcinoma cells showed the highest levels of SAA. Expression was also found in colon carcinoma metastases. Cells of lymphoid follicles of the intestinal wall, inflammatory cells, ganglion cells, and endothelial cells, also expressed SAA mRNA. Immunohistochemical staining revealed SAA protein expression that colocalized with SAA mRNA expression. RT-PCR analysis confirmed the expression of the SAA1 and SAA4 genes in colon carcinomas, expression that was barely detectable in normal colon tissues. These findings indicate local and differential expression of SAA in human colon cancer tissues and suggest its role in colonic tumorigenesis.

NF-kappaB functions as a tumour promoter in inflammation-associated cancer.

The causes of sporadic human cancer are seldom recognized, but it is estimated that carcinogen exposure and chronic inflammation are two important underlying conditions for tumour development, the latter accounting for approximately 20% of human cancer. Whereas the causal relationship between carcinogen exposure and cancer has been intensely investigated, the molecular and cellular mechanisms linking chronic inflammation to tumorigenesis remain largely unresolved. We proposed that activation of the nuclear factor kappaB (NF-kappaB), a hallmark of inflammatory responses that is frequently detected in tumours, may constitute a missing link between inflammation and cancer. To test this hypothesis, we studied the Mdr2-knockout mouse strain, which spontaneously develops cholestatic hepatitis followed by hepatocellular carcinoma, a prototype of inflammation-associated cancer. We monitored hepatitis and cancer progression in Mdr2-knockout mice, and here we show that the inflammatory process triggers hepatocyte NF-kappaB through upregulation of tumour-necrosis factor-alpha (TNFalpha) in adjacent endothelial and inflammatory cells. Switching off NF-kappaB in mice from birth to seven months of age, using a hepatocyte-specific inducible IkappaB-super-repressor transgene, had no effect on the course of hepatitis, nor did it affect early phases of hepatocyte transformation. By contrast, suppressing NF-kappaB inhibition through anti-TNFalpha treatment or induction of IkappaB-super-repressor in later stages of tumour development resulted in apoptosis of transformed hepatocytes and failure to progress to hepatocellular carcinoma. Our studies thus indicate that NF-kappaB is essential for promoting inflammation-associated cancer, and is therefore a potential target for cancer prevention in chronic inflammatory diseases.

Adhesion of human platelets to serum amyloid A.

Serum amyloid A (SAA) is an acute phase reactant, and its level in the blood is elevated to 1000-fold in response of the body to trauma, infection, inflammation, and neoplasia. SAA was reported to inhibit platelet aggregation and to induce adhesion of leukocytes. This study looked at adhesion of human platelets to SAA. Immobilized SAA supported the adhesion of human washed platelets; level of adhesion to SAA was comparable to fibronectin and lower than to fibrinogen. Adhesion to SAA was further enhanced by Mn(2+) and the physiological agonist, thrombin. Platelet adhesion to SAA was completely abolished by anti-SAA antibody. SAA-induced adhesion was inhibited by antibodies against the integrin receptor alphaIIbbeta3, by the peptide GRGDSP and by SAA-derived peptide containing YIGSR-like and RGD-like adhesion motifs (amino acids 29 to 42). Adhesion was not inhibited by control immunoglobulin G, by antibody against the integrin receptor alphaVbeta3, by the peptide GRGESP, and by SAA-derived peptide that includes incomplete RGD motif. SAA-derived peptide 29 to 42 also inhibited platelet adhesion to fibronectin. Transfected human melanoma cells expressing alphaIIbbeta3 adhered to SAA, whereas transfected cells expressing alphaVbeta3 did not. By using flow cytometry, the alphaIIbbeta3 cells displayed significantly higher levels of binding of soluble SAA than the alphaVbeta3 cells. These data indicate that human platelets specifically adhere to SAA in an RGD- and alphaIIbbeta3-dependent manner. Thus, SAA may play a role in modulating platelet adhesion at vascular injury sites by sharing platelet receptors with other platelet-adhesive proteins.

Effect of colchicine and cytokines on MEFV expression and C5a inhibitor activity in human primary fibroblast cultures.

BACKGROUND: Familial Mediterranean fever is an autosomal recessive disease characterized by sporadic attacks of inflammation affecting the serosal spaces. The gene associated with FMF (MEFV), mainly expressed in neutrophils, was recently found to be expressed also in primary cultures of serosal origin (peritoneal and synovial fibroblasts). A C5a inhibitor, previously detected in normal serosal fluids, was recently identified in serosal cultures as well, and was found to be deficient in serosal fluids and cultures obtained from FMF patients. OBJECTIVE: To investigate the effect of colchicine (the main therapeutic agent for FMF patients) and certain inflammatory cytokines (IL-1 beta, TNF-alpha, IFN-alpha, IFN-gamma) on MEFV expression and C5a inhibitor activity in neutrophils and primary peritoneal fibroblast cultures. METHODS: Human primary peritoneal fibroblast cultures and neutrophils were studied for MEFV expression and C5a inhibitor activity, using reverse transcription-polymerase chain reaction and C5a-induced myeloperoxidase assay, respectively, in the presence and absence of colchicine and cytokines. RESULTS: MEFV expression in neutrophils was high and could not be induced further. Its expression in the peritoneal fibroblasts was lower than in neutrophils and could be induced using colchicine and cytokines parallel with induction of C5a inhibitor activity. Semi-quantitative RT-PCR assays enabled estimation of MEFV induction by the cytokines at 10-100-fold and could not be further increased by concomitant addition of colchicine. CONCLUSION: Serosal tissues, which are afflicted in FMF, express colchicine and cytokine-inducible MEFV and contain inducible C5a inhibitor activity. The relation between the ability of colchicine to induce MEFV and C5a inhibitor activity, and its efficacy in FMF treatment, require further investigation.