Profiling of adrenocorticotropic hormone and arginine vasopressin in human pituitary gland and tumor thin tissue sections using droplet-based liquid-microjunction surface-sampling-HPLC–ESI-MS–MS

Abstract

Described here are the results from the profiling of the proteins arginine vasopressin (AVP) and adrenocorticotropic hormone (ACTH) from normal human pituitary gland and pituitary adenoma tissue sections using a fully automated droplet-based liquid microjunction surface sampling-HPLC-ESI-MS/MS system for spatially resolved sampling, HPLC separation, and mass spectral detection. Excellent correlation was found between the protein distribution data obtained with this droplet-based liquid microjunction surface sampling-HPLC-ESI-MS/MS system and those data obtained with matrix assisted laser desorption ionization (MALDI) chemical imaging analyses of serial sections of the same tissue. The protein distributions correlated with the visible anatomic pattern of the pituitary gland. AVP was most abundant in the posterior pituitary gland region (neurohypophysis) and ATCH was dominant in the anterior pituitary gland region (adenohypophysis). The relative amounts of AVP and ACTH sampled from a series of ACTH secreting and non-secreting pituitary adenomas correlated with histopathological evaluation. ACTH was readily detected at significantly higher levels in regions of ACTH secreting adenomas and in normal anterior adenohypophysis compared to non-secreting adenoma and neurohypophysis. AVP was mostly detected in normal neurohypophysis as anticipated. This work demonstrates that a fully automated droplet-based liquid microjunction surface sampling system coupled to HPLC-ESI-MS/MS can be readily used for spatially resolved sampling, separation, detection, and semi-quantitation of physiologically-relevant peptide and protein hormones, such as AVP and ACTH, directly from human tissue. In addition, the relative simplicity, rapidity and specificity of the current methodology support the potential of this basic technology with further advancement for assisting surgical decision-making.

Extraction efficiency and implications for absolute quantitation of propranolol in mouse brain, liver and kidney tissue sections using droplet-based liquid microjunction surface sampling high-performance liquid chromatography/electrospray ionization tande

“…Typically, pictures of the junction before and after solvent dispense, and of the surface after solvent aspirations, were collected for all extraction cycles. Glass slides were mounted in a 3D‐printed spring‐loaded microtiter‐plate‐size sample holder . The sample holder was then placed into an open tray of the HTS PAL autosampler and the analysis locations in each sample were selected with a laser distance sensor using software developed in house (dropletProbe Premium v1.20).…”

“…Liquid extraction‐based surface sampling probes of different types are receiving increased attention due to their enhanced sensitivity compared with other ambient surface sampling techniques . and to their ability to integrate with HPLC/MS systems . These techniques for spatially resolved sampling rely on liquid‐solid extraction of material from the tissue.…”

“…[19][20][21][22] and to their ability to integrate with HPLC/MS systems. [23][24][25][26][27][28][29][30][31] These techniques for spatially resolved sampling rely on liquid-solid extraction of material from the tissue. No modifications to existing tissue sections are required to employ the technique.…”

Ambient Mass Spectrometry Imaging Using Direct Liquid Extraction Techniques

“…54 Plug formation mode enables analyte preconcentration and reactive analysis. 51 LMJ-SSP has been used for the analysis of molecules separated on TLC plates, 47 tissue profiling, 55,56 and spatial mapping of metabolites in microbial 57 and fungal communities. 58 …”

An open port sampling interface for liquid introduction atmospheric pressure ionization mass spectrometry

“…Since that time multiple continuous flow as well as discrete droplet variations of this liquid microjunction surface sampling and analysis approach have been implemented for numerous applications. Some of these liquid microjunction probes/methods allow ready transfer of the sampled material for post‐sampling processing, such as a high‐performance liquid chromatography (HPLC) separation, prior to mass spectral analysis . Such a configuration enables effective analysis of targeted analytes within complex matrices as well as the ability to differentiate isobaric compounds, thus providing a greater degree of chemical information from a single spot sample than is possible with a direct analysis.…”