The sphingosine-1-phosphate (S1P) lysophospholipid receptor S1P3 regulates MAdCAM-1+ endothelial cells in splenic marginal sinus organization

Marginal zones (MZs) are microdomains in the spleen that contain various types of immune cells, including MZ B cells, MOMA1(+) metallophilic macrophages, and mucosal addressin cell adhesion molecule 1 (MAdCAM-1)(+) endothelial cells. MAdCAM-1(+) and MOMA1(+) cells line the sinus, that separates MZs from splenic follicles. Here we show that a receptor for the lysophospholipid sphingosine-1-phosphate (S1P), S1P(3), is required for normal numbers of splenic immature and MZ B cells, and for S1P-induced chemotaxis of MZ B cells. S1P(3) is also essential for proper alignment of MOMA1(+) macrophages and MAdCAM-1(+) endothelial cells along the marginal sinus. The lack of cohesion of the marginal sinus in S1P(3)(-/-) mice affects MZ B cell functions, as wild-type (WT) MZ B cells migrate more into S1P(3)(-/-) follicles than into WT follicles after treatment with lipopolysaccharide. Additionally, short-term homing experiments demonstrate that WT MZ B cells home to the S1P(3)(-/-) spleen in increased numbers, suggesting a role for the marginal sinus in regulating MZ B cells numbers. Moreover, S1P(3)(-/-) mice are defective in mounting immune responses to thymus-independent antigen type 2 due to defects in radiation-resistant cells in the spleen. These data identify lysophospholipids and the S1P(3) receptor as essential regulators of the MZ sinus and its role as a barrier to the follicle.     

Keeping central venous lines open: a prospective comparison of heparin,vitamin C and sodium chloride sealing solutions in medical patients

OBJECTIVE: To prevent catheter occlusion, intermittently used central venous catheters are frequently sealed with vitamin C solution or heparin solution between use. The present study was designed to test the effectiveness of this approach and to compare the efficiency of sealing solutions. DESIGN AND SETTING: Prospective randomized study performed on a 9-bed medical ICU and on medical wards of an academic tertiary care center. PARTICIPANTS. Ninety-nine central venous line placements were prospectively included in the study and randomized into three treatment groups: sodium chloride 0.9%, vitamin C (200 mg/ml) and heparin (5000 IU/ml) sealing solutions. INTERVENTIONS AND MEASUREMENTS: Catheters were filled with the respective sealing solution and patency was tested once every 2 days using a standardized routine. Catheter patency was compared among the three groups using Kaplan-Meier statistics and log-rank testing. RESULTS: There was a significant difference in catheter patency between the three groups (p<0.03, log-rank test). A comparison of catheter survival between the catheters filled with heparin and those filled with sodium chloride, but not between those filled with vitamin C solution and with sodium chloride solution, exhibited significant differences in catheter patency (p<0.04, log-rank test). CONCLUSIONS: Local anticoagulation of intermittently used central venous catheters prolongs catheter patency. High-dose (5000 IU/ml) heparin solution is a useful anticoagulant for this purpose, while vitamin C solution does not prolong catheter patency.     

Gc-globulin concentrations and C5 haplotype-tagging polymorphisms contribute to variations in serum activity of complement factor C5

OBJECTIVES: To investigate the role of Gc-globulin and C5 gene variants as co-factors in the regulation of profibrogenic C5 serum activities. DESIGN: Retrospective clinical investigation with 100 healthy probands. Genomic DNA was isolated from whole blood and examined for the human C5 htSNPs rs17611 and rs2300929. Actin-free Gc-globulin-, total Gc-globulin- and total C5-concentrations in serum were measured using ELISA assays; C5 activities in serum were determined using radial immunodiffusion. RESULTS: C5 serum concentrations were significantly elevated in individuals carrying at least one profibrogenic allele of the C5 htSNP rs17611, but no association between C5 htSNPs and C5 serum activities was detected, albeit C5 activities correlated positively with C5 concentrations in serum. However, C5 activities were also positively correlated with total and actin-free Gc-globulin concentrations. CONCLUSION: Our findings indicate that C5 gene variants and Gc-globulin levels co-define the proinflammatory and profibrogenic effects of C5 in patients at-risk for progression of liver fibrosis.     

Plasminogen fragment K1-5 improves survival in a murine hepatocellular carcinoma model

BACKGROUND: The prognosis of patients with hepatocellular carcinoma (HCC) remains poor, and new alternative treatments are needed. AIMS: To comparatively test the angiostatic and antitumour effects of adenoviral gene transfer of angiostatin (PlgK1-4, amino acids 1-440) and full kringles 1-5 (PlgK1-5, amino acids 1-546) in a model of subcutaneously transferred HCC in mice. METHODS: PlgK1-4 and PlgK1-5 were generated from human WtPlg cDNA and used for adenovirus construction. Vector function and angiostatic effects were confirmed in vitro and in vivo. Antitumoral efficacies of intratumoral vector injections were studied in a model of subcutaneously transferred HCC model. RESULTS: Cell supernatants containing PlgK1-4 and PlgK1-5 reduced endothelial tube formation in vitro by about 30%, whereas WtPlg exerted no inhibitory effect. Endothelial cell infiltration in vivo was decreased by about 60%, but not in AdWtPlg-treated animals. Intratumoral treatment of subcutaneous HCC tumours inhibited growth by 40% for AdPlgK1-4 and 63% for AdPlgK1-5 in surviving mice 12 days after initiation of treatment, whereas treatment with AdWtPlg even led to accelerated growth. Although PlgK1-4 and PlgK1-5 have similar inhibitory effects on intratumoral microvessels, PlgK1-5 markedly improved the survival time compared with PlgK1-4. CONCLUSION: PlgK1-5 and PlgK1-4 effectively inhibited HCC growth. As PlgK1-5 could also prolong the survival time, inducing complete tumour elimination in half of the AdPlgK1-5-treated mice, PlgK1-5 might be the most potential plasminogen fragment for treatment of experimental HCC.     

From bone to breast and back - the bone cytokine RANKL and breast cancer

Receptor activator of nuclear factor-κB ligand (RANKL) plays a pivotal role in regulating bone homeostasis. Osteoporosis and malignant bone disease secondary to breast cancer are characterized by enhanced RANKL production and increased bone turnover. Thus, denosumab, a monoclonal antibody to RANKL, has been developed and is now approved for various bone loss conditions. Recent results indicate that RANKL may also promote the development and osseous migration of breast cancer.     

Expression and localization of the uptake transporters OATP2B1, OATP3A1 and OATP5A1 in non-malignant and malignant breast tissue

Organic anion transporting polypeptides (OATPs, gene family SLCO/SLC21) mediate the uptake of multiple endogenous substances such as estrogens and estrogen metabolites and of several widely prescribed drugs (e.g. statins, antibiotics and anticancer agents) into cells. Since several anticancer agents have been identified as substrates for OATPs, these transporters may also have an impact on cancer treatment. Expression of OATPs has been identified in colon, pancreatic and gastric carcinomas but to date little is known about the expression and localization of OATP family members in non-malignant breast tissue and breast cancer. We therefore analyzed the mRNA expression of all human OATP family members and further evaluated the mRNA amount of the highly-expressed OATPs OATP2B1, OATP3A1 and OATP5A1 in 10 paired samples of normal breast tissue and breast cancer. Furthermore, the tissue-specific localization of these OATPs was investigated. The results demonstrated that the mRNA expression of OATPs in normal and malignant breast tissue shows a high interindividual variability and that no significant differences in the mRNA amount between normal and malignant tissue could be detected. Furthermore, we localized OATP3A1 and OATP5A1 to the plasma membrane of epithelial cells of the lactiferous ducts in normal breast tissue. In breast cancer, both OATPs are highly expressed in the plasma membrane and in the cytoplasm. Since estrogen and estrogen metabolites as well as anticancer agents are substrates for OATPs these results indicate the possibility of OATP-mediated uptake of hormones during breast cancer development and an impact of certain OATPs on chemotherapeutic cancer treatment.