A possible Fourier transform infrared‐based plasma fingerprint of angiotensin‐converting enzyme inhibitor‐induced reversal of endothelial dysfunction in diabetic mice

Abstract

Angiotensin-converting enzyme inhibitors (ACE-I) display vasoprotective activity and represent the cornerstone in the treatment of cardiovascular diseases. In this study, we tested whether Fourier transform infrared (FTIR)-based analysis of blood plasma is sensitive to detect vasoprotective effects of treatment with perindopril including reversal of endothelial dysfunction in diabetes. For this purpose, plasma samples were collected from untreated db/db mice, db/db mice treated with 2 or 10 mg/kg perindopril and db+ mice. The effect of perindopril on endothelial function was examined in ex vivo aortic rings; 10 mg/kg but not 2 mg/kg of perindopril reversed endothelial dysfunction. In plasma of db/db mice, the balance between conformations of plasma proteins was noted, and treatment with perindopril at a high dose but not at a low dose reversed this effect. This was revealed by amide II/amide I ratio attributed to increased β-sheet formation. Spectral markers at 3010, 1520/1238 cm , representative for unsaturation degree of lipids and phosphorylation of tyrosine, respectively, were also affected by perindopril treatment. In conclusion, although metabolic abnormalities associated with type 2 diabetes mellitus such as hypertriglyceridemia and hyperglycemia strongly affected spectral FTIR profile of diabetic plasma, we identified FTIR features that seem to be associated with the vasoprotective activity of ACE-I.

Fourier transform infrared spectroscopic signature of blood plasma in the progression of breast cancer with simultaneous metastasis to lungs

“…This trend is found in agreement with two other IR markers specific for fatty acids chains, that is, ratio of the methyl to methylene groups [( ν as (CH 3 ) + ν s (CH 3 ))/( ν as (CH 2 ) + ν s (CH 2 )] and ratio of the olefinic group to the lipid content [ ν (═CH)/( ν as (CH 2 ) + ν s (CH 2 )]. A ratio [ ν as (CH 3 ) + ν s (CH 3 ))/( ν as (CH 2 ) + ν s (CH 2 )] displays changes in the length of fatty acyl chains as suggested in the literature (Figure IB) . Shortening of phospholipids chains progresses gradually and is significantly elevated in the late phase characterized by the formation of macrometastases.…”

“…Shortening of phospholipids chains progresses gradually and is significantly elevated in the late phase characterized by the formation of macrometastases. In turn, the integral intensity of the olefinic ═CH band, which can be used to determine the concentration of double bonds present in unsaturated fatty acids and a level of lipid peroxidation, shows the opposite tendency to changes than displayed in the graph 4.I.B (see Figure IC) . FTIR spectra of plasma exhibit a significant drop down of unsaturated lipids already in the early micrometastatic phase (week 2), and this decrease is continuously observed up to the macrometastatic phase on week 4.…”

Biochemical detection of fatal hypothermia and hyperthermia in affected rat hypothalamus tissues by Fourier transform infrared spectroscopy

“…However, the band shapes below 1530 cm −1 in the resultant difference spectra are quite different. The absorbance value at around 1518 cm −1 , arising from tyrosine side chains [ 67 ], decreases in the case of the fatal hypothermia group but increases in the case of the fatal hyperthermia group. This finding suggests a different concentration of tyrosine-rich proteins in the fatal hypothermia and hyperthermia groups.…”

“…The FTIR-based amide profiles have proven to be valuable for examining the content, structure and function of tissue proteins [ 67 , 79 ]. Here, the sum of intensities of protein amide I band (1700−1600 cm −1 ), which corresponds mainly to the C = O stretching modes of the protein backbone [ 80 ], were calculated to illustrate the total protein level ( Figure 6 A), while the intensity of 1622 cm −1 was calculated to represent the level of aggregated proteins ( Figure 6 B) [ 52 , 53 ].…”

FTIR, Raman and AFM characterization of the clinically valid biochemical parameters of the thrombi in acute ischemic stroke

“…FTIR image of the organic matter distribution was constructed by integration of the 2800–3100 cm −1 region, which is especially intense for bands of the methylene and olefinic groups (Fig. 2B) 15–17 . This spectral region easily differentiates the clot areas rich in the lipid fraction due to the presence of long-chain fatty acids and also can be used for lipids quantification as shown previously 18 .…”