FTIR spectroscopy confirms age-related changes in protein conformation in a new independent dataset of human plasma samples

Abstract

The loss of proteostasis is a key hallmark of aging and has been well documented using several model systems. However, in biofluids such as blood plasma, little is known about how the loss of proteostasis affects protein conformation during aging. Our previous work has demonstrated age-related changes in protein conformation in human plasma samples using FTIR spectroscopy and conformation-specific antibodies. To prove the potential of spectroscopy to detect slight changes in protein secondary structure during aging, we have applied the same methodology to a new and independent set of 24 human plasma samples from donors with ages ranging from 40 to 75 years. The results clearly show that from middle to old age there is a decrease in antiparallel β-sheet structures and an increase in intermolecular β-sheets, indicative of an increase in aggregation-prone proteins in human plasma over time. This confirms the potential of FTIR spectroscopy as a technique to evaluate protein conformational changes related to health and disease and as a suitable method to be used in a clinical setting to produce quick and reliable results.