Surface Tension and Intrinsic Amyloid Fluorescence of Serum and Cerebrospinal Fluid Samples in Alzheimer´S Disease

Abstract

Aim: Surface tension of biological fluids can be influenced by changes in oligomerization or aggregation of surfactant peptides or proteins. Amphiphilic peptides of amyloid-β or other amyloidogenic peptides/proteins display properties of surfactants, oligomerization and aggregation increase also their fluorescence intensity compared with native structures. Results/methodology: We estimated surface tension and native/ThioflavinT-based/intrinsic amyloid fluorescence intensity in serum and cerebrospinal fluid samples for their evalution as diagnostic biomarkers for Alzheimer´s disease (AD). Discussion/conclusion: Our results indicate that values of surface tension are not a suitable biomarker for AD. However, the ratio of ThioflavinT-based fluorescence to intrinsic amyloid fluorescence in cerebrospinal fluid appears to be an acceptable supportive diagnostic biomarker for AD (its sensitivity was 61.1%, and the specificity 70.8% when compared with aged controls).

Keywords:

• Alzheimer´s disease
• amyloid fluorescence
• biological samples
• biomarkers
• normal aging
• surface tension

Ethical conduct of research

All subjects gave written informed consent regarding study participation, in accordance with the Declaration of Helsinky. The Ethics Committee of the Third Faculty of Medicine, Charles University in Prague approved the study.

Financial & competing interests disclosure

In Slovakia, the study was supported by VEGA 2/0145/17, COST project 083/14 action BM1405 (MVTS), SAS-MOST JRP 2015/5 and EU project 6220120033. We would like to thank Dagmar Sedlakova (Institute of Experimental Physics, SAS, Kosice, Slovakia) for technical assistance. In the Czech Republic, the study was supported by GACR (P304-12-G069), AZV (16-27611A) and NPU I (LO1611) projects. Moreover, NV18-07-00272 and PROGRES Q 35 projects supported this study in the Czech Republic. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Additional information

Funding

In Slovakia, the study was supported by VEGA 2/0145/17, COST project 083/14 action BM1405 (MVTS), SAS-MOST JRP 2015/5 and EU project 6220120033. We would like to thank Dagmar Sedlakova (Institute of Experimental Physics, SAS, Kosice, Slovakia) for technical assistance. In the Czech Republic, the study was supported by GACR (P304-12-G069), AZV (16-27611A) and NPU I (LO1611) projects. Moreover, NV18-07-00272 and PROGRES Q 35 projects supported this study in the Czech Republic. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.