Extracellular matrix proteins in bile and serum of patients with gallstone disease

Lipid and protein corona of food-grade TiO2 nanoparticles in simulated gastrointestinal digestion

In the presence of biological matrices, engineered nanomaterials, such as TiO₂, develop a biomolecular corona composed of lipids, proteins, etc. In this study, we analyzed the biocorona formed on the food grade TiO₂ (E171) going through an in vitro simulated gastrointestinal digestion system in either a fasting food model (FFM), a standardized food model (SFM), or a high fat food model (HFFM). Lipids and proteins were extracted from the biocorona and underwent untargeted lipidomic and label-free shotgun proteomic analyses. Our results showed that the biocorona composition was different before and after food digestion. After digestion, more diverse lipids were adsorbed compared to proteins, most of which were the enzymes added to the simulated digestion system. The corona lipid profile was distinct from the digested food model they presented in, although similarity in the lipid profiles between the corona and the food matrix increased with the fat content in the food model. The corona formed in the two low-fat environments of FFM and SFM shared a higher degree of similarity while very different from their corresponding matrix, with some lipid species adsorbed with high enrichment factors, indicating specific interaction with the TiO₂ surface outperforming lipid matrix concentration in determination of corona formation. Formation of the biocorona may have contributed to the reduced oxidative stress as well as toxicological impacts observed in cellular studies. The present work is the first to confirm persistent adsorption of biomolecules could occur on ingested nanomaterials in food digestae. More future studies are needed to study the in vivo impacts of the biocorona, and shed lights on how the biocorona affects the biotransformations and fate of the ingested nanomaterials, which may impose impacts on human health.

The immunohistochemistry of invasive and proliferative phenotype switching in melanoma: a case report

To date there is no effective therapy for metastatic melanoma and at the molecular level the disease progression is poorly understood. A recent study by our group led to the development of a novel phenotype switching model for melanoma progression, wherein cells transition back-and-forth between states of proliferation and invasion to drive disease progression. To explore the model's clinical relevance we interrogated phenotype-specific expression patterns in human melanoma patient material. A matched primary/metastasis pair from a human melanoma patient was obtained and immunohistochemically stained for proliferative and invasive phenotype markers. These were also stained for hypoxia and blood vessel markers. Proliferative phenotype markers Melan-A and Mitf showed consistent anti-correlation with invasive phenotype marker Wnt5A and hypoxia marker Glut-1. These also correlated with observed intra-tumoural vascularization patterns. Similar pattern distributions were present in both primary and metastasis samples. Strikingly, we observed that late phase metastatic melanoma cells adopt morphologies and behaviours identical to very early phase cells. The expression patterns observed closely matched expectations derived from previous in vitro and xenografting experiments. These results highlight the likelihood that disease progression involves melanoma cells retaining the capacity to regulate the expression of metastatic potential critical factors according to changing microenvironmental conditions.

Fibronectin in human bile fluid for diagnosis of malignant biliary diseases

In a preliminary study, we demonstrated a strong association between the concentration of the glycoprotein fibronectin (FN) in human bile fluid and the presence of malignant biliary diseases. We now present the results of measurements of total FN (tFN) and cellular FN (cFN) within a larger group of 71 patients. Bile fluid was collected during routine endoscopic retrograde cholangiography or by transhepatic puncture, respectively, from patients admitted for examination/treatment of biliary obstruction. Determination of tFN in bile was performed using a previously described time-resolved fluorescence immunoassay (TRFIA). For cFN, a newly developed TRFIA, using a specific monoclonal antibody for the EDA epitope of cFN, was applied. Within the noncarcinoma group of patients (n=50), consistently low concentrations of tFN (median = 5 ng/mL) were found. In most of these cases, the corresponding concentrations of cFN were below the detection limit (2.6 ng/mL) of this assay. Highly significantly elevated concentrations were found for both tFN (median = 1,220 ng/mL) and cFN (median = 243 ng/mL) in the carcinoma group (n = 21) in comparison with the noncarcinoma group (P < or = .01). By adopting cutoff values of 60 ng/mL for tFN and >0 ng/mL for cFN, diagnostic sensitivities for carcinoma of the biliary tract of 0.89 and 0.92, and specificities of 0.96 and 0.98, respectively, were computed. FN in bile fluid is suggested as a sensitive, specific, and easily determined marker for differential diagnosis of malignant and benign diseases of the biliary tract.