Soluble Transferrin Receptor (sTfR) Identifies Iron Deficiency Anemia (IDA) in Pulmonary Tuberculosis Patients.

BACKGROUND: iron deficiency in pulmonary tuberculosis (TB) patients may weaken their immune system, causing difficulty in overcoming the infection. Accurate diagnosis of iron deficiency anemia (IDA) in pulmonary TB patients is essential. In order to prove the iron deficient state, diagnosis should focus on inflammatory factors, which could highly affect the outcome of iron status, such as measurement of serum ferritin (SF). Soluble Transferrin Receptor (sTfR) is the best parameter to diagnose iron deficiency in the inflammatory condition. This study aimed to understand the role of sTfR to identify IDA in TB patients. METHODS: cross-sectional study were applied to 3 study groups: anemic pulmonary TB (68 subjects), IDA (7 subjects), and non-anemic pulmonary TB (15 subjects). The test averages and correlations between sTfR, SF, and other hematological parameters were measured and analyzed. RESULTS: significant differences of sTfR were found in the anemic TB group compared to the IDA group and also between the IDA and non-anemic TB groups (p<0.0001). However, there was no significant difference (p>0.05) between TB anemic and non-anemic groups. We also found no significant difference between the TB anemic sub-group with normal levels of sTfR compared with the non-anemic group. There was no significant difference of sTfR levels between sub-group of increasing sTfR and group IDA (p>0.05). However, there was strong correlation between sTfR and SF in the IDA group (r=-0.89; p=0.007). CONCLUSION: the findings suggest verifying the sTfR amount in anemic patients with pulmonary TB suffering from inflammation, so that the iron deficiency could be more accurately identified and properly treated.

The Function of ß2-glycoprotein I in Angiogenesis and Its in Vivo Distribution in Tumor Xenografts.

Intact ß2-glycoprotein I (iß2GPI) is a glycoprotein that regulates coagulation and fibrinolysis. Nicked ß2GPI (nß2GPI) possesses an angiogenic property at a relatively low concentration, and an antiangiogenic property at a high concentration. Here we investigated the functions of ßi 2GPI and nß2GPI in vascular endothelial growth factor (VEGF)-A-induced endothelial cell proliferation and tube formation. We used noninvasive PET imaging to analyze the ｉｎ　ｖｉｖｏ distribution of intravenously injected ß2GPI variants in tumor lesions in mice. iß2GPI was incubated with plasmin to obtain nß2GPI, and its N-terminal sequence was analyzed. nß2GPI had at least one other cleavage site upstream of the ß2GPI's domain V, whereas the former plasmin-cleavage site locates between K317 and T318. Both of intact and nicked ß2GPI significantly inhibited the VEGF-A-induced cell proliferation and the tube formation of human umbilical vein endothelial cells (HUVECs). PET imaging visualized considerably distributed intensities of all tested ß2GPI variants in tumor lesions of pancreatic tumor cell-xenografts. These results indicate that ß2GPI may be physiologically and pathophysiologically important in the regulation of not only coagulation and fibrinolysis, but also angiogenesis.

Mutants of ß2-glycoprotein I: Their features and potent applications.

ß2-Glycoprotein I (ß2GPI) is a highly-glycosylated plasma protein composed of five homologous domains which regulates coagulation, fibrinolysis, and/or angiogenesis by interacting to negatively charged hydrophobic molecules and/or with plasminogen and its metabolites. The present study focused on structural and functional characterization of ß2GPI's domain I (DI) and V (DV). Through N-terminal amino acid sequencing, a novel plasmin-cleaved site at K287C288 was identified in DV. We further modified the intact DV by altering two amino acids at specific proteolytic cleavage sites to generate three stable DV mutants: DV(PP), (PE), and (AA). Results of both SDS-PAGE and MALDI-TOF-MS showed that all three DV mutants were more stable than the intact DV, and DV(PE) was predominantly resistant to proteolysis. Competitive ELISA assessed affinities of intact ß2GPI and those mutants to cardiolipin. In culture system, all DV and DI mutants potently inhibited HUVEC's proliferation by 18-30% as compared to control. Only DI and nicked ß2GPI showed significant inhibition in HUVEC's tube formation. Moreover, DV(PE)-coated affinity columns demonstrated its binding property towards anionic lipids and could substantially isolate anionic DOPS from zwitterionic DOPC as a purification model. In summary, the proteolytic resistant and unhindered phospholipid (PL) binding properties of DV(PE) have made it an appealing element for subsequent prospective studies. Future in-depth characterization and optimized applications of cleavage-resistant DV(PE) would complement its full capacity as a novel clinical modality in the field of vascular imaging and/or lipidomics studies.