[phys4phys] BioPhysLab seminar: Sebastian Frische, Thursday, December 8th 2022, 12:00

[Aleksandar Krmpot]

Dear colleagues,

You are cordially invited to the BioPhysLab seminar, which will be held
(in person!) on Thursday,  December 8th 2022 at 12:00 in the library
reading room "Dr. Dragan Popović" of the Institute of Physics Belgrade.
The talk entitled

"ASP+ Shows Amplified Fluorescence by Binding to Albumin and Is
Accumulated In Vivo"

will be given by Sebastian Frische, Ph.D. Associate professor (Dept. of
Biomedicine, Aarhus University, Aarhus, Denmark) 

The abstract of the talk:

Organic cations (OC) is excreted by the kidney by transcellular
transport in the proximal tubule. Since manu OC's are classified as
uremic toxins, which are difficult to remove by dialysis in kidney
patients, clinical evaluation of proximal tubular secretion of organic
cations is desired, but difficult.  
The biomedical knowledge on OC secretion and cellular transport partly
relies on studies using the fluorescent tracer
4-dimethylaminostyryl)-N-methylpyridinium (ASP+), which has been used in
many studies of renal excretion mechanisms of organic ions and which
could be a candidate as a PET tracer. This study is aimed at expanding
the knowledge of the tracer characteristics of ASP+ by recording the
distribution and intensity of ASP+ signals in vivo both by fluorescence
and by positron emission tomography (PET) imaging and at investigating
if the fluorescence signal of ASP+ is influenced by the presence of
albumin.  
Two-photon in vivo microscopy of male Münich Wistar Frömter rats showed
that a bolus injection of ASP+ conferred a fluorescence signal to the
blood plasma lasting for about 30 minutes. In the renal proximal tubule,
the bolus resulted in a complex pattern of fluorescence including a
rapid and strong transient signal at the brush border, a very low signal
in the luminal fluid, and a slow transient intracellular signal. PET
imaging using 11C-labelled ASP+ showed accumulation in the liver, heart,
and kidney. Fluorescence emission spectra recorded in vitro of ASP+
alone and in the presence of albumin using both 1-photon excitation and
two-photon excitation showed that albumin strongly enhance the emission
from ASP+ and induce a shift of the emission maximum from 600 to 570 nm.
 
Conclusion. The renal pattern of fluorescence observed from ASP+in vivo
is likely affected by the local concentration of albumin, and
quantification of ASP+ fluorescent signals in vivo cannot be directly
translated to ASP+ concentrations. 

Sincerely,  
---

dr Aleksandar J. Krmpot, naucni savetnik
BioPhysLab
Institut za fiziku, Pregrevica 118, 11080 Beograd-Zemun, SRBIJA

dr. Aleksandar J. Krmpot, research professor
BioPhysLab
Institute of Physics, Pregrevica 118, 11080 Belgrade- Zemun, SERBIA

telefon/phone:  +381 11 3713 012
mobilni/cell:   +381 64 202 65 62
e-posta/e-mail: krmpot at ipb.ac.rs
www.hemmaginero.rs [1] 
www.ipb.ac.rs [2] 
http://www.ipb.ac.rs/en/istrazivanja/laboratorije-2/laboratorija-za-biofiziku/


  

Links:
------
[1] http://www.hemmaginero.rs
[2] http://www.ipb.ac.rs
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