Lipid imaging within the normal rat kidney using silver nanoparticles by matrix-assisted laser desorption/ionization mass spectrometry

Abstract

The well-characterized cellular and structural components of the kidney show distinct regional compositions and distribution of lipids. In order to more fully analyze the renal lipidome we developed a matrix-assisted laser desorption/ionization mass spectrometry approach for imaging that may be used to pinpoint sites of changes from normal in pathological conditions. This was accomplished by implanting sagittal cryostat rat kidney sections with a stable, quantifiable and reproducible uniform layer of silver using a magnetron sputtering source to form silver nanoparticles. Thirty-eight lipid species including 7 ceramides, 8 diacylglycerols, 22 triacylglycerols, and cholesterol were detected and imaged in positive ion mode. Thirty-six lipid species consisting of, 7 sphingomyelins, 10 phosphatidylethanolamines, 1 phosphatidylglycerol, 7 phosphatidylinositols and 11 sulfatides, were imaged in negative ion mode for a total of seventy-four high resolution lipidome maps of the normal kidney. Thus, our approach is a powerful tool not only for studying structural changes in animal models of disease, but also for diagnosing and tracking stages of disease in human kidney tissue biopsies.

Laser Desorption/Ionization Mass Spectrometric Imaging of Endogenous Lipids from Rat Brain Tissue Implanted with Silver Nanoparticles

“…Additionally, cholesterol adducted with three silver atoms and cholesteryl esters (CE) plus one silver atom were observed as minor peaks. The assignment of M+Ag 3 for cholesterol has been discussed in an earlier study [6]. The major peak for cholesterol is a plusone silver atom adduct.…”

“…A few of the most abundant PCs were observed as +Ag and +K adducts. However, despite the high abundance of PCs in brain tissue, these mass peaks were very low in intensity due to nanoparticle matrices preference for ionizing more neutral lipids [5,6,23].…”

“…Gold cluster ion currents, although proving the potential of the technique, were insufficient for implantation of the large areas necessary for organ imaging. More recently, an alternative method for homogeneous implantation of metalnanoparticulate ions into tissue enables reproducible MILDI-MS imaging after 500 eV implantation of 8 nm AgNP into heart [5], kidney [6], and brain [7,8] unfixed cryostat sections. In the brain studies, MILDI-MS imaging was used to study injury and pathology in controlled cortical impact [7] and alcoholism [8] using rodent models.…”

MALDI mass spectrometric imaging meets “omics”: recent advances in the fruitful marriage

“…Alternatively, an automated registration procedure can be performed, 145 which ultimately facilitates the correlation to anatomical atlases. Besides the identification, the number of detected metabolites is important, which can be increased by carrying out the MALDI MSI analysis in both, positive and negative ionisation mode, using certain matrices (1,5-diaminonaphthalene, 84 quercetin, 86 dithranol, 88 silver nanoparticles 164 or the combination of two (cyano-4-hydoxycinnamic acid and 9-aminoacrdine). 147 Besides, cancer applications, various other diseases, such as infections of hepatitis B virus, 81 atherosclerosis, 148 fabry, 79 peridontal, 149 alzheimer's, [150][151][152] epilepsia, 153 stroke, 154 schizophrenia, 155 and stargardt disease 82 have been investigated to shade light into the underlying disease mechanism.…”

Simultaneous detection of phosphatidylcholines and glycerolipids using matrix‐enhanced surface‐assisted laser desorption/ionization‐mass spectrometry with sputter‐deposited platinum film

“…Recently, a surface‐assisted laser desorption/ionization (SALDI)‐IMS method using Ag nanoparticles was shown to allow the detection of DAG in the kidney. Na and K, 107 Ag, 109 Ag adduct ions, and fragment ions were obtained slightly, although Ag nanoparticles (AgNPs) were proven to be an effective matrix for the analysis of DAG containing double bonds . In the study, authors reported that ultaviolet absorption wavelength of AgNPs caused the low efficiencies of desorption and ionization.…”