# Slot Blot- and Electrospray Ionization–Mass Spectrometry/Matrix-Assisted Laser Desorption/Ionization–Mass Spectrometry-Based Novel Analysis Methods for the Identification and Quantification of Advanced Glycation End-Products in the Urine

## TL;DR

This paper introduces new methods to detect and measure harmful compounds called AGEs in urine, which could help diagnose lifestyle-related diseases early.

## Contribution

A novel analytical strategy combining slot blotting and mass spectrometry for detecting low-concentration AGEs in urine.

## Key findings

- The proposed method can detect AGE-modified proteins, peptides, and free AGEs in urine.
- Takata’s lysis buffer and polyvinylidene difluoride membrane enhance detection sensitivity.
- The approach is non-invasive and suitable for early diagnosis of lifestyle-related diseases.

## Abstract

Proteins, saccharides, and low molecular organic compounds in the blood, urine, and saliva could potentially serve as biomarkers for diseases related to diet, lifestyle, and the use of illegal drugs. Lifestyle-related diseases (LSRDs) such as diabetes mellitus (DM), non-alcoholic steatohepatitis, cardiovascular disease, hypertension, kidney disease, and osteoporosis could develop into life-threatening conditions. Therefore, there is an urgent need to develop biomarkers for their early diagnosis. Advanced glycation end-products (AGEs) are associated with LSRDs and may induce/promote LSRDs. The presence of AGEs in body fluids could represent a biomarker of LSRDs. Urine samples could potentially be used for detecting AGEs, as urine collection is convenient and non-invasive. However, the detection and identification of AGE-modified proteins in the urine could be challenging, as their concentrations in the urine might be extremely low. To address this issue, we propose a new analytical approach. This strategy employs a method previously introduced by us, which combines slot blotting, our unique lysis buffer named Takata’s lysis buffer, and a polyvinylidene difluoride membrane, in conjunction with electrospray ionization-mass spectrometry (ESI)/matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). This novel strategy could be used to detect AGE-modified proteins, AGE-modified peptides, and free-type AGEs in urine samples.