456
K. malek et al.
within the amyloid plaques [128]. this animal model expresses a chimeric mouse/
human amyloid precursor protein gene and a mutant human presenilin 1 gene, allowing the mice to secrete a human β-amyloid peptide. Although FTIR imaging
confirms an increase in the protein content within the plaques by 61 % in comparison to the surrounding region, only a 29 % increase in Zn was observed compared
to Cu (less by 22 %), Fe (less by 17 %), and Ca (less by 7 %). In the human Ad tissue, the concentration of metal ions increased by 908, 1171, 573, and 9838 %, respectively. this suggests that metals may exhibit a weaker influence on the progression of Ad in transgenic mouse than in human Ad, and therefore this model may be
a limited representation of human Ad pathology [128]. despite this, the PSAPP
mouse model has been used in the FtIR examination of unsaturated lipid levels in
the hippocampus tissue during aging (13–56 weeks) [129]. the presence of these
macromolecules affects some functions of the brain such as membrane fluidity or
signal transduction, while their degradation may signal lipid peroxidation. Firstly,
uhCA of recorded IR images divided the hippocampus section into the three subregions of interest corresponding to the axonal, dendritic, and somatic layers. Average spectra extracted from each layer revealed the decrease in content of lipids in
this order. Next, PCA analysis showed the disappearance of the unsaturated lipid
band centred ca. 3015 cm
−1
in the axonal layer for the PSAPP group compared to
the control group for 56 week-old animals. tracking the changes in intensity of this
band reveals an increase in lipid unsaturation in the control mice with age, but not
in the Ad transgenic group. this fact indicates that the accumulation of unsaturated
lipids in healthy animals is associated with the alteration of fatty acid composition
during brain development. In turn, the deficiency in these macromolecules in the
sis of long-chain polyunsaturated fatty acids during the disease progression or Aβmediated lipid peroxidation. this study also shows that the Ad pathogenesis can
occur in the white matter of the brain too [129]. other spectral markers of Ad diseased tissue are proposed from an animal model experiment, in which the hippocampal, cortical, and caudal tissues of transgenic tgCRNd8 mice were examined
by synchrotron FtIR mapping and correlated with Raman spectroscopy [130]. this
animal model expresses double mutant amyloid precursor protein and displays
dense-cored plaques in the brain. the analysis of IR spectra showed the presence of
a sharp band at 1304 cm
−1
in the tgCRNd8 tissues, which corresponded to localisation of crystalline inclusions. this band is assigned to creatine and its highest content is observed in the hippocampus of an advanced Ad brain (the 72-week-old
transgenic mice). the creatine band is also observed in IR images of post mortem
human tissue of the hippocampus originating from two Alzheimer diseased patients
[130]. the presence of creatine is associated with reduced metabolism of the Ad
brain, since this molecule with phosphocreatine regulates energy balance in the
brain. this process is observed in the dementia-related disorders and may indicate a
disturbed function of mitochondrial creatine kinase catalysing creatine phosphorylation [130]. A few creatine deposits can appear in normal ageing (in > 14-month
mice), but more than 30 deposits randomly distributed in the hippocampus were
already detected in the 5-month tgCRNd8 brain, and this number increased
K. malek et al.
within the amyloid plaques [128]. this animal model expresses a chimeric mouse/
human amyloid precursor protein gene and a mutant human presenilin 1 gene, allowing the mice to secrete a human β-amyloid peptide. Although FTIR imaging
confirms an increase in the protein content within the plaques by 61 % in comparison to the surrounding region, only a 29 % increase in Zn was observed compared
to Cu (less by 22 %), Fe (less by 17 %), and Ca (less by 7 %). In the human Ad tissue, the concentration of metal ions increased by 908, 1171, 573, and 9838 %, respectively. this suggests that metals may exhibit a weaker influence on the progression of Ad in transgenic mouse than in human Ad, and therefore this model may be
a limited representation of human Ad pathology [128]. despite this, the PSAPP
mouse model has been used in the FtIR examination of unsaturated lipid levels in
the hippocampus tissue during aging (13–56 weeks) [129]. the presence of these
macromolecules affects some functions of the brain such as membrane fluidity or
signal transduction, while their degradation may signal lipid peroxidation. Firstly,
uhCA of recorded IR images divided the hippocampus section into the three subregions of interest corresponding to the axonal, dendritic, and somatic layers. Average spectra extracted from each layer revealed the decrease in content of lipids in
this order. Next, PCA analysis showed the disappearance of the unsaturated lipid
band centred ca. 3015 cm
−1
in the axonal layer for the PSAPP group compared to
the control group for 56 week-old animals. tracking the changes in intensity of this
band reveals an increase in lipid unsaturation in the control mice with age, but not
in the Ad transgenic group. this fact indicates that the accumulation of unsaturated
lipids in healthy animals is associated with the alteration of fatty acid composition
during brain development. In turn, the deficiency in these macromolecules in the
sis of long-chain polyunsaturated fatty acids during the disease progression or Aβmediated lipid peroxidation. this study also shows that the Ad pathogenesis can
occur in the white matter of the brain too [129]. other spectral markers of Ad diseased tissue are proposed from an animal model experiment, in which the hippocampal, cortical, and caudal tissues of transgenic tgCRNd8 mice were examined
by synchrotron FtIR mapping and correlated with Raman spectroscopy [130]. this
animal model expresses double mutant amyloid precursor protein and displays
dense-cored plaques in the brain. the analysis of IR spectra showed the presence of
a sharp band at 1304 cm
−1
in the tgCRNd8 tissues, which corresponded to localisation of crystalline inclusions. this band is assigned to creatine and its highest content is observed in the hippocampus of an advanced Ad brain (the 72-week-old
transgenic mice). the creatine band is also observed in IR images of post mortem
human tissue of the hippocampus originating from two Alzheimer diseased patients
[130]. the presence of creatine is associated with reduced metabolism of the Ad
brain, since this molecule with phosphocreatine regulates energy balance in the
brain. this process is observed in the dementia-related disorders and may indicate a
disturbed function of mitochondrial creatine kinase catalysing creatine phosphorylation [130]. A few creatine deposits can appear in normal ageing (in > 14-month
mice), but more than 30 deposits randomly distributed in the hippocampus were
already detected in the 5-month tgCRNd8 brain, and this number increased