Quantitation of Plasma Levels of Tetranectin - Effects of Oral Contraceptives, Pregnancy, Treatment with L-Asparaginase and Liver Cirrhosis

Comparative analysis of serum proteomes: Identification of proteins associated with sciatica due to lumbar intervertebral disc herniation

Lumbar intervertebral disc herniation (LDH) is one of the most common orthopedic conditions that can cause lower back pain and sciatica. However, the pathogenesis of LDH is poorly understood. The aim of the present study was to use proteomic analysis of blood samples to establish whether there are serum proteins associated with LDH, which may be useful in elucidating LDH pathogenesis. The ultimate aim was to develop a simple technique for the diagnosis of LDH based on the blood samples of patients with sciatica. The study used comparative analysis of serum proteomes associated with sciatica due to LDH. A total of 30 LDH patients with sciatica, receiving treatment between August and December 2007, were selected as the experimental group (or LDH group). A total of 2 ml of blood was obtained from each of the 30 patients in the LDH group and from 30 healthy volunteers, who constituted the control group. Two-dimensional electrophoresis of the blood samples was conducted, distinct protein spots were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and proteins associated with LDH were detected. An enzyme-linked immunosorbent assay (ELISA) was developed to screen for the LDH proteins and was tested on the sera of a second test and control group that included 10 patients with LDH and 10 healthy subjects, respectively. Based on signal intensity, the expression levels of 6 proteins on the dielectrophoretogram were found to be significantly associated with LDH. The identities of the LDH proteins were upregulated apolipoprotein-L1 (APO-L1) and two types of serum albumin precursors, and downregulated apolipoprotein M (APO-M), tetranectin (TN) and immunoglobulin light chain (IGL). Further ELISA experiments confirmed that there were increased serum levels of 4 out of the 6 proteins in patients with sciatica due to LDH, which was statistically different compared to the healthy subjects. In conclusion, these results suggest that serum APO-L1, TN, APO-M and IGL may serve as LDH biomarkers.

Expression and prognostic significance of Tetranectin in invasive and non-invasive bladder cancer

Tetranectin (TN) is a plasminogen kringle-4 binding protein that can be detected in the plasma and the extracellular matrix. In malignancies, TN is thought to enhance proteolytic processes enabling tumor cells to invade and metastasize. So far, TN expression has not been described in transitional cell bladder cancer (TCC), and there is no information on the prognostic significance of its in situ expression. TN expression was studied in 99 TCC patients diagnosed between 1994 and 1997. Immunohistochemistry was performed on a tissue microarray using a monoclonal antibody against TN (clone 11F1). Within the mean follow-up period of 60 months, pTa and pT2-4 TCC patients with stainable TN in the tumor stroma had a significant shorter recurrence-free survival and higher risk of recurrence compared to those without stainable TN (p = 0.0002 for both). TN expression in the tumor cells did not influence recurrence-free survival. In conclusion, TN is expressed in a subgroup of bladder cancer patients with a higher risk of recurrence who may take benefit from a closer follow-up.

Changes in plasma tetranectin following hip surgery with or without thrombotic complications

The fibrinolytic system seems to play a role in the development of postoperative thromboembolic complications (DVT). The newly described tetrameric protein tetranectin (TN), which has been found to enhance the activation of plasminogen to plasmin, therefore was studied in 55 patients who had total hip replacement and solely elastic stockings as physical thromboprophylaxis. No significant difference in plasma TN was found between the 5 patients with DVT and those without DVT, neither preoperatively or postoperatively at day 0, 1, 3, 7 or 10. A significant decrease in plasma TN was found from preoperative to postoperative values, indicating that TN may be a possible marker for other postoperative events. Because of the observed postoperative decrease it is important to consider the sampling time in the future research with TN.

Tetranectin in amniotic fluid, maternal serum and fetal fluids

The concentration of the newly discovered protein tetranectin has been measured in different fetal and maternal compartments. In amniotic fluid a significant, positive correlation between the tetranectin concentration and gestational age was found (a mean of 0.2 mg l-1 at week 14 to a mean of 0.5 mg l-1 at week 21). In maternal serum a slight negative correlation was found between tetranectin concentration and gestational week (a mean of 6.17 mg l-1 at week 14 to a mean of 5.79 mg l-1 at week 21). In-term cord blood collected at delivery a mean level of 6.0 mg l-1 was found, and no difference was found between arterial- and venous-blood tetranectin concentration. In fetal serum the overall mean level was 2.6 mg l-1 and a significant positive correlation between tetranectin concentration and gestational age was found. The mean level was 1.1 mg l-1 in fetal cerebrospinal fluid and no correlation to gestational age was found. Fetal tetranectin may, therefore, be correlated to fetal maturation.

Differences in tetranectin immunoreactivity between benign and malignant breast tissue

Tetranectin (TN) is a human, plasminogen kringle 4 binding plasma protein with ubiquitous cellular distribution and lectin-like characteristics. By means of the peroxidase-antiperoxidase staining technique a polyclonal and a monoclonal antibody were used to demonstrate TN within the intracellular as well as the extracellular compartment of invasive breast carcinoma. Whereas cell associated TN was universal showing only quantitative differences depending of the growth pattern of the tumor, 78 of 133 tumors displayed TN extracellularly as well. The occurrence of this stromal TN immunoreactivity was closely associated with desmoplasia, recognized morphologically by an increase in fibroblastic cells and immunohistochemically by an intense staining for the connective tissue glycoprotein fibronectin (FN). Benign breast tissue displayed a universal, intense cytoplasmic but no extracellular reaction for TN, with the exception of rare foci of granulation tissue and around dilated cysts. Functional studies have shown that human embryonal lung fibroblasts increase their release of TN to the growth medium upon stimulation. The presence of TN extracellularly within fibroblast-rich foci of desmoplasia (and granulation tissue) suggests that a similar increased release of the protein takes place in vivo during active states. Desmoplasia has been found to have a protective effect on tumor cell propagation and metastasis in a murine model. The molecular interactions, which are responsible for this effect, are undoubtedly complex. However, TN may, by its specific binding to kringle 4 of plasminogen and its high affinity for sulphated polysaccharides, add to the understanding of how plasminogen activation is modulated at the local extracellular level.