location of parasites and define metabolic and cellular changes associated with their
presence in human endothelial cells of cerebral microvessels. The chemometric
approach enabled to distinguish healthy cells from infected ones on the basis of
alterations in the lipids and nucleic acids composition. These research show that
endothelial cells are the target of the attack by the protozoa.
The largest number of endothelial cell research focus on the analysis of changes
in their lipid profiles. Two original papers deal with the formation of lipid droplets
(LDs) in human aortic endothelial cells (HAoECs) under the influence of polyunsaturated fatty acids [83, 84]. These studies are based on Raman and fluorescence
microscopies. Due to the high resolving power of the methods, the size and distribution of LDs in the cytoplasm of cells in three-dimensional projections were
determined. The use of CA and comparison with Raman spectra of lipid standards
enabled to define the chemical composition of LDs. The appearance of characteristic bands at 1660 and 3015 cm
–1 originating from the stretching vibrations of the
C=C and =C–H groups, respectively, and the calculated values of the degree of
unsaturation confirmed the presence of unsaturated fatty acids and their storage in
the form of LDs. In addition, the effect of 1-methylnicotinamide (MNA) on the
uptake of arachidonic acid (AA) sodium salt was checked [84]. The evidence has
been provided that MNA may act as a cationic carrier to facilitate the uptake of
negatively charged AA ions, which may have physiological and pharmacological
significance. The topic of LDs was also investigated by Astantina et al. [85], who
provided a further evidence of the active LDs function, concluding that LDs are
involved as carriers in intercellular communication between HMEC-1 cells.
The formation of LDs in the cytoplasm of cells is associated also with the
inflammatory process. Inflammation in cellular models has been studied using many
spectroscopic and microscopic methods. A review on methods of imaging LDs,
starting from classical methods involving staining with fluorescence detection to
modern imaging methods, e.g., coherent anti-Stokes Raman spectroscopy (CARS),
is provided in the work by Melo et al. [86]. Some reports on the use of AFM
technique for the study of endothelial cells and macrophages can be also found [87,
88]. The inflammation of endothelial cells is the first symptom of blood vessel
pathology in cardiovascular diseases. The body’s aim is to reduce pathogen invasion and damage after tissue disruption. On the cellular scale, it is the response to
proinflammatory factors, i.e., tumor necrosis factor alpha (TNF-a) or lipopolysaccharides (LPS) followed by various mechanisms activated via connection of
inflammatory factors to the specific membrane receptors [89]. All these factors
trigger activation of NF-jB protein pathway, which transmits information about the
pathogen to the cell nucleus, from which the inflammatory response occurs.
Endothelial cells also show increased synthesis of PGI 2 prostacyclin, which triggers
the arachidonic acid pathway through a series of prostaglandins. PGI 2 is considered
a marker of inflammation. Spectroscopic studies shed the new light on this process.
Czamara et al. [90] applied 3D Raman profiling combined with chemometric
analysis to study the in vitro model of inflammation. In this work, HMEC-1 cells
exposed to TNF-a exhibited formation of two types of LDs: more saturated,
composed mainly of phosphatidylcholine and saturated cholesteryl esters and much
6 Small and Large Molecules Investigated by Raman Spectroscopy
173
presence in human endothelial cells of cerebral microvessels. The chemometric
approach enabled to distinguish healthy cells from infected ones on the basis of
alterations in the lipids and nucleic acids composition. These research show that
endothelial cells are the target of the attack by the protozoa.
The largest number of endothelial cell research focus on the analysis of changes
in their lipid profiles. Two original papers deal with the formation of lipid droplets
(LDs) in human aortic endothelial cells (HAoECs) under the influence of polyunsaturated fatty acids [83, 84]. These studies are based on Raman and fluorescence
microscopies. Due to the high resolving power of the methods, the size and distribution of LDs in the cytoplasm of cells in three-dimensional projections were
determined. The use of CA and comparison with Raman spectra of lipid standards
enabled to define the chemical composition of LDs. The appearance of characteristic bands at 1660 and 3015 cm
–1 originating from the stretching vibrations of the
C=C and =C–H groups, respectively, and the calculated values of the degree of
unsaturation confirmed the presence of unsaturated fatty acids and their storage in
the form of LDs. In addition, the effect of 1-methylnicotinamide (MNA) on the
uptake of arachidonic acid (AA) sodium salt was checked [84]. The evidence has
been provided that MNA may act as a cationic carrier to facilitate the uptake of
negatively charged AA ions, which may have physiological and pharmacological
significance. The topic of LDs was also investigated by Astantina et al. [85], who
provided a further evidence of the active LDs function, concluding that LDs are
involved as carriers in intercellular communication between HMEC-1 cells.
The formation of LDs in the cytoplasm of cells is associated also with the
inflammatory process. Inflammation in cellular models has been studied using many
spectroscopic and microscopic methods. A review on methods of imaging LDs,
starting from classical methods involving staining with fluorescence detection to
modern imaging methods, e.g., coherent anti-Stokes Raman spectroscopy (CARS),
is provided in the work by Melo et al. [86]. Some reports on the use of AFM
technique for the study of endothelial cells and macrophages can be also found [87,
88]. The inflammation of endothelial cells is the first symptom of blood vessel
pathology in cardiovascular diseases. The body’s aim is to reduce pathogen invasion and damage after tissue disruption. On the cellular scale, it is the response to
proinflammatory factors, i.e., tumor necrosis factor alpha (TNF-a) or lipopolysaccharides (LPS) followed by various mechanisms activated via connection of
inflammatory factors to the specific membrane receptors [89]. All these factors
trigger activation of NF-jB protein pathway, which transmits information about the
pathogen to the cell nucleus, from which the inflammatory response occurs.
Endothelial cells also show increased synthesis of PGI 2 prostacyclin, which triggers
the arachidonic acid pathway through a series of prostaglandins. PGI 2 is considered
a marker of inflammation. Spectroscopic studies shed the new light on this process.
Czamara et al. [90] applied 3D Raman profiling combined with chemometric
analysis to study the in vitro model of inflammation. In this work, HMEC-1 cells
exposed to TNF-a exhibited formation of two types of LDs: more saturated,
composed mainly of phosphatidylcholine and saturated cholesteryl esters and much
6 Small and Large Molecules Investigated by Raman Spectroscopy
173