461
15 FtIR Imaging of tissues: techniques and methods of Analysis
infarction [148]. the observation of collagen fibrosis by using FtIR imaging has
been also reported for the cardiomyopathy induced by an infection with coxsackievirus, recognized as a highly active etiological agent in the development of myocarditis [149]. FtIR images constructed for a collagen band and lipid/protein ratio
show similar results to those observed for cardiomyopathic hamsters [147]. No differences are observed for early, chronic, and acute stages of the infection [149]. All
of them exhibited ca. 26 % increase in the collagen content along with a significant
reduction of lipids in comparison to the control group. this may suggest a similar
etiology of cardiac dysfunction with a possible genetic and viral origin [149].
other experiments have linked diabetes of type I [150] and early life growth restriction [151] with alternations of biochemical composition of the myocardia. Both
the experiments have shown different spectroscopic variations across the entire
spectral region in the disordered myocardia. this confirms that FtIR spectroscopy
is a sensitive tool in detecting and/or monitoring various cardiac diseases and/or
their pathogenesis. In the case of diabetic-induced changes in rat hearts, IR mapping
was performed for both ventricles and the vein in the left ventricle. In the diseased
myocardium, some spectral changes were found to be specific for the ventricles or
veins only, whereas other spectral changes exhibit a similar pattern in all the investigated areas. For instance, an increase in content of olefinic acids (the 3012 cm
−1
band) and collagen (the 1201 cm
−1
band) were only observed in the vein of the left
ventricle. Whilst the calculated lipid/protein ratio increases in the entire area of
the myocardium in diabetic rats, but it is smaller in the right ventricle than in the
left one and its veins. the authors suggested that the accumulation of lipids due to
damage of the mitochondria in diabetic 5-week old rats results from improper metabolism of cardiac lipids. Such a lipid accumulation has been previously observed
for diabetic 14-week old rats. Furthermore, FtIR spectra also revealed variation in
protein secondary structure. The amide I band attributed to α-helical structures is
present at ca. 1656 cm
−1
in the healthy myocardium, whereas the second band at
1637 cm
−1
, typical for β-pleated sheet conformations appears in the diabetic tissue.
A significant increase of the latter is observed in the left ventricle, while reduction
of the α-helix band intensity was found to be specific for the right ventricle. These
conformational changes are presumed to result from the covalent attachment of
glucose to amino groups of proteins that consequently lead to the rearrangement
of protein structures. there is also an apparent glycogen accumulation accompanied by a reduction in content of cholesterol esters in the diabetic hearts, since the
1151/1171 cm
−1
ratio decreases in the diabetic group with respect to the control one.
In addition, the increase in intensity of a band at 1041 cm
−1
indicates an accumulation of oligo- and polysaccharides [150].
Zohdi et al. have demonstrated the effect of a low protein diet during pregnancy
and lactation on biochemical changes in the left ventricle of the rat myocardium
[151]. FtIR false colour images were constructed by using uhCA in the fingerprint
region, while the total protein and lipid content was assessed by integration of the
amide II and C = o stretching bands, respectively. In addition, a band at 1228 cm
−1
,
called the “mixed” band, exhibited contributions from the amide III mode of proteins, the ν as (Po 2
−
) vibration of phospholipids and/or phosphorylated proteins, and
15 FtIR Imaging of tissues: techniques and methods of Analysis
infarction [148]. the observation of collagen fibrosis by using FtIR imaging has
been also reported for the cardiomyopathy induced by an infection with coxsackievirus, recognized as a highly active etiological agent in the development of myocarditis [149]. FtIR images constructed for a collagen band and lipid/protein ratio
show similar results to those observed for cardiomyopathic hamsters [147]. No differences are observed for early, chronic, and acute stages of the infection [149]. All
of them exhibited ca. 26 % increase in the collagen content along with a significant
reduction of lipids in comparison to the control group. this may suggest a similar
etiology of cardiac dysfunction with a possible genetic and viral origin [149].
other experiments have linked diabetes of type I [150] and early life growth restriction [151] with alternations of biochemical composition of the myocardia. Both
the experiments have shown different spectroscopic variations across the entire
spectral region in the disordered myocardia. this confirms that FtIR spectroscopy
is a sensitive tool in detecting and/or monitoring various cardiac diseases and/or
their pathogenesis. In the case of diabetic-induced changes in rat hearts, IR mapping
was performed for both ventricles and the vein in the left ventricle. In the diseased
myocardium, some spectral changes were found to be specific for the ventricles or
veins only, whereas other spectral changes exhibit a similar pattern in all the investigated areas. For instance, an increase in content of olefinic acids (the 3012 cm
−1
band) and collagen (the 1201 cm
−1
band) were only observed in the vein of the left
ventricle. Whilst the calculated lipid/protein ratio increases in the entire area of
the myocardium in diabetic rats, but it is smaller in the right ventricle than in the
left one and its veins. the authors suggested that the accumulation of lipids due to
damage of the mitochondria in diabetic 5-week old rats results from improper metabolism of cardiac lipids. Such a lipid accumulation has been previously observed
for diabetic 14-week old rats. Furthermore, FtIR spectra also revealed variation in
protein secondary structure. The amide I band attributed to α-helical structures is
present at ca. 1656 cm
−1
in the healthy myocardium, whereas the second band at
1637 cm
−1
, typical for β-pleated sheet conformations appears in the diabetic tissue.
A significant increase of the latter is observed in the left ventricle, while reduction
of the α-helix band intensity was found to be specific for the right ventricle. These
conformational changes are presumed to result from the covalent attachment of
glucose to amino groups of proteins that consequently lead to the rearrangement
of protein structures. there is also an apparent glycogen accumulation accompanied by a reduction in content of cholesterol esters in the diabetic hearts, since the
1151/1171 cm
−1
ratio decreases in the diabetic group with respect to the control one.
In addition, the increase in intensity of a band at 1041 cm
−1
indicates an accumulation of oligo- and polysaccharides [150].
Zohdi et al. have demonstrated the effect of a low protein diet during pregnancy
and lactation on biochemical changes in the left ventricle of the rat myocardium
[151]. FtIR false colour images were constructed by using uhCA in the fingerprint
region, while the total protein and lipid content was assessed by integration of the
amide II and C = o stretching bands, respectively. In addition, a band at 1228 cm
−1
,
called the “mixed” band, exhibited contributions from the amide III mode of proteins, the ν as (Po 2
−
) vibration of phospholipids and/or phosphorylated proteins, and