Identification of a beta-amyloid-binding plasma protein, LRP1: implications for biomarker research and therapy in Alzheimer's disease

Low levels of soluble low-density lipoprotein receptor-related protein 1 in patients with type 2 diabetes mellitus and diabetic retinopathy

Low-density lipoprotein receptor-related protein-1 (LRP-1) is a large transmembrane receptor. LRP-1 plays a role in diverse cellular processes, including lipid metabolism, cell growth, migration, and regeneration. Soluble form of LRP-1 (sLRP-1) can be detected in serum. sLRP-1 can serve as a biomarker of atherosclerosis and cardiometabolic diseases. This study investigated the concentrations of the circulating serum sLRP-1 in patients with retinopathy and type 2 diabetes mellitus. Fifty-two patients with diabetic retinopathy and 71 controls were enrolled based on well-defined eligibility criteria. Venous blood samples were collected after 12 h of fasting. sLRP-1 concentrations were measured using the commercially available ELISA in an accredited laboratory. The mean age of patients and control groups were 63.6 and 48.5 years, respectively. The median disease duration was 8.1 years. The median serum sLRP-1 levels were lower in patients with diabetic retinopathy compared to the controls (2.11 μg/mL versus 2.44 μg/mL, p = 0.034). No significant correlation was observed between the sLRP-1 and serum lipid levels. The sLRP-1 levels are low in patients with diabetic retinopathy compared to healthy controls, and future studies are needed to assess sLRP-1 as a potential biomarker in diabetic retinopathy.

Exosomal Aβ-Binding Proteins Identified by "In Silico" Analysis Represent Putative Blood-Derived Biomarker Candidates for Alzheimer´s Disease

The potential of exosomes as biomarker resources for diagnostics and even for therapeutics has intensified research in the field, including in the context of Alzheimer´s disease (AD). The search for disease biomarkers in peripheral biofluids is advancing mainly due to the easy access it offers. In the study presented here, emphasis was given to the bioinformatic identification of putative exosomal candidates for AD. The exosomal proteomes of cerebrospinal fluid (CSF), serum and plasma, were obtained from three databases (ExoCarta, EVpedia and Vesiclepedia), and complemented with additional exosomal proteins already associated with AD but not found in the databases. The final biofluids’ proteomes were submitted to gene ontology (GO) enrichment analysis and the exosomal Aβ-binding proteins that can constitute putative candidates were identified. Among these candidates, gelsolin, a protein known to be involved in inhibiting Abeta fibril formation, was identified, and it was tested in human samples. The levels of this Aβ-binding protein, with anti-amyloidogenic properties, were assessed in serum-derived exosomes isolated from controls and individuals with dementia, including AD cases, and revealed altered expression patterns. Identification of potential peripheral biomarker candidates for AD may be useful, not only for early disease diagnosis but also in drug trials and to monitor disease progression, allowing for a timely therapeutic intervention, which will positively impact the patient’s quality of life.