Eclectic characterisation of chemically modified cell-derived matrices obtained by metabolic glycoengineering and re-assessment of commonly used methods

Azide-bearing cell-derived extracellular matrices (“clickECMs”) have emerged as a highly exciting new class of biomaterials. They conserve substantial characteristics of the natural extracellular matrix (ECM) and offer simultaneously small abiotic functional groups that enable bioorthogonal bioconjugation reactions. Despite their attractiveness, investigation of their biomolecular composition is very challenging due to the insoluble and highly complex nature of cell-derived matrices (CDMs). Yet, thorough qualitative and quantitative analysis of the overall material composition, organisation, localisation, and distribution of typical ECM-specific biomolecules is essential for consistent advancement of CDMs and the understanding of the prospective functions of the developed biomaterial. In this study, we evaluated frequently used methods for the analysis of complex CDMs. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and (immune)histochemical staining methods in combination with several microscopic techniques were found to be highly eligible. Commercially available colorimetric protein assays turned out to deliver inaccurate information on CDMs. In contrast, we determined the nitrogen content of CDMs by elementary analysis and converted it into total protein content using conversion factors which were calculated from matching amino acid compositions. The amount of insoluble collagens was assessed based on the hydroxyproline content. The Sircol™ assay was identified as a suitable method to quantify soluble collagens while the Blyscan™ assay was found to be well-suited for the quantification of sulphated glycosaminoglycans (sGAGs). Eventually, we propose a series of suitable methods to reliably characterise the biomolecular composition of fibroblast-derived clickECM.

Common characterisation methods for cell-derived extracellular matrices (ECMs) are compared using both unmodified and azide-bearing fibroblast-derived ECM.     

Association between SNPs in defined functional pathways and risk of early or late toxicity as well as individual radiosensitivity

Background and purpose

The aim of this study was to determine the impact of functional single nucleotide polymorphism (SNP) pathways involved in the ROS pathway, DNA repair, or TGFB1 signaling on acute or late normal toxicity as well as individual radiosensitivity.

Materials and methods

Patients receiving breast-conserving surgery and radiotherapy were examined either for erythema (n?=?83), fibrosis (n?=?123), or individual radiosensitivity (n?=?123). The 17 SNPs analyzed are involved in the ROS pathway (GSTP1, SOD2, NQO1, NOS3, XDH), DNA repair (XRCC1, XRCC3, XRCC6, ERCC2, LIG4, ATM) or TGFB signaling (SKIL, EP300, APC, AXIN1, TGFB1). Associations with biological and clinical endpoints were studied for single SNPs but especially for combinations of SNPs assuming that a SNP is either beneficial or deleterious and needs to be weighted.

Results

With one exception, no significant association was seen between a single SNP and the three endpoints studied. No significant associations were also observed when applying a multi-SNP model assuming that each SNP was deleterious. In contrast, significant associations were obtained when SNPs were suggested to be either beneficial or deleterious. These associations increased, when each SNP was weighted individually. Detailed analysis revealed that both erythema and individual radiosensitivity especially depend on SNPs affecting DNA repair and TGFB1 signaling, while SNPs in ROS pathway were of minor importance.

Conclusion

Functional pathways of SNPs may be used to form a risk score allowing to predict acute and late radiation-induced toxicity but also to unravel the underlying biological mechanisms.

     

Relationship Between Minor Myocardial Damage and Inflammatory Acute-Phase Reaction in Acute Coronary Syndromes

Background: In severe acute coronary syndromes (ACS) elevation of markers of inflammation and acute phase reaction (APR) like C-reactive protein (CRP) as well as a release of troponin have been reported.Using a high sensitivity troponin T (TnT) test we investigated whether an APR occurs in ACS only in the presence of ischemic myocardial damage. Methods: In 85 patients with ACS C-reactive protein (CRP), serum amyloid A (SAA), fibrinogen, thrombin antithrombin III complexes (TAT) and kallikrein were determined vs. high sensitive TnT (0.02 ng/ml) initially and 2 d later vs. 45 patients with stable angina pectoris and 42 controls. Results: In stable angina pectoris, markers of inflammation and coagulation were slightly elevated (p < 0.05). Initially in ACS elevations of CRP to 1.2 ± 0.3 mg/dl, SAA to 4.8 ± 2.6 mg/dl and fibrinogen to 448 ± 21 mg/dl (all p < 0.01 vs. controls) were found followed by a significant APR (p < 0.01).In the subgroup of TnT positive ACS patients, an APR with increased CRP (4.1 ± 1.3 mg/dl), SAA (20.4 ± 8.3 mg/dl), and fibrinogen (641 ± 45 mg/dl) was detectable (all p < 0.05 vs. TnT negative patients). In contrast, patients without TnT release showed APR markers comparable to patients with stable angina pectoris. Conclusion: Our findings demonstrate an association between myocardial injury in ACS and acute phase reaction as evidenced by several molecular markers. A highly sensitive TnT-test identified myocardial inury in about all patients with APR while a standard TnT cut-off (0.1 ng/ml) missed 32% of these patients. Thus, the APR in patients with ACS is strongly associated with at least minor ischemic myocardial damage and prior findings of an APR independent from myocardial injury are probably based on less sensitive troponin tests.     

Erythrocyte indexes, iron metabolism, and hyperhomocysteinemia in adults with cyanotic congenital cardiac disease

A high percentage of cyanotic adults (37%) with cyanotic congenital cardiac disease (CCD) presented with depleted iron stores (13 of 52) or latent iron deficiency (6 of 52), even in a CCD center in which cyanotic patient phlebotomy is mostly avoided. In many of these patients, hypochromia and microcytosis was frequent, whereas hyperchromia and macrocytosis were relatively common.Furthermore, 50% of patients presented with hyperhomocysteinemia, possibly related to folate or B vitamin deficiencies, which may increase red blood cell size and color, explaining the lack of microcytosis and hypochromia in many cyanotic patients with iron deficiency.     

In Vitro Activity of wALADin Benzimidazoles against Different Life Cycle Stages of Plasmodium Parasites

wALADin1 benzimidazoles are specific inhibitors of δ-aminolevulinic acid dehydratase from Wolbachia endobacteria of filarial nematodes. We report that wALADin1 and two derivatives killed blood stage Plasmodium falciparum in vitro (50% inhibitory concentrations, 39, 7.7, and 12.8 μM, respectively). One of these derivatives inhibited gliding motility of Plasmodium berghei ANKA infectious sporozoites with nanomolar affinity and blocked invasion into hepatocytes but did not affect intrahepatocytic replication. Hence, wALADin1 benzimidazoles are tools to study gliding motility and potential antiplasmodial drug candidates.