Desorption electrospray ionization-based imaging of interaction between vascular graft and human body.

The desorption electrospray ionization-mass spectrometry imaging (DESI-MSI) is known as a fast and convenient MS-based method for lipid imaging in various biological materials. Here, we applied this technique to visualize lipid distribution in a vascular graft removed from a patient's body. This is a good example of the DESI system capabilities toward imaging of interaction between artificial material and living tissues. Detailed analysis allowed for visualization of the spatial distribution of selected lipids in this implanted, artificial material. Not only DESI-MSI allowed visualization of lipid distribution in the investigated material but also enabled identification of the detected molecular species using MS/MS. Here, this technique was successfully used to evaluate the saturation and spatial distribution of endogenous lipids in the artificial vascular graft. Unambiguous identification of the lipids was done with the aid of fragmentation procedure. We also showed that various lipids localize preferably in graft material or internal plaque existing inside the graft.

Cathepsin E (EC 3.4.23.34)--a review.

Cathepsin E belongs to the third class of enzymes - hydrolases, a subclass of peptide bond hydrolases and a sub-subclass of endopeptidases with aspartic catalytic sites. Cathepsin E is an endopeptidase with substrate specificity similar to that of cathepsin D. In a human organism, cathepsin E occurs in: erythrocytes, thymus, dendritic cells, epithelial M cells, microglia cells, Langerhans cells, lymphocytes, epithelium of gastrointestinal tract, urinary bladder, lungs, osteoclasts, spleen and lymphatic nodes. In human cells, loci of the gene of pre-procathepsin E are located on chromosome 1 in the region 1231-32. The catalytic site of cathepsin E is two residues of aspartic acid - Asp96 and Asn281, occurring in amino acid triads with sequences DTG96-98 and DTG281-283. To date, no particular role of cathepsin E in the metabolism of proteins in normal tissues has been found. However, it is known that there are many documented pathological conditions in which overexpression of cathepsin E occurs.