Acrolein but not its metabolite, 3-Hydroxypropylmercapturic acid (3HPMA), activates vascular transient receptor potential Ankyrin-1 (TRPA1): Physiological to toxicological implications.

Acrolein, an electrophilic α,ß-unsaturated aldehyde, is present in foods and beverages, and is a product of incomplete combustion, and thus, reaches high ppm levels in tobacco smoke and structural fires. Exposure to acrolein is linked with cardiopulmonary toxicity and cardiovascular disease risk. The hypothesis of this study is the direct effects of acrolein in isolated murine blood vessels (aorta and superior mesenteric artery, SMA) are transient receptor potential ankyrin-1 (TRPA1) dependent. Using isometric myography, isolated aorta and SMA were exposed to increasing levels of acrolein. Acrolein inhibited phenylephrine (PE)-induced contractions (approximately 90%) in aorta and SMA of male and female mice in a concentration-dependent (0.01-100 µM) manner. The major metabolite of acrolein, 3-hydroxypropylmercapturic acid (3HPMA), also relaxed PE-precontracted SMA. As the SMA was 20× more sensitive to acrolein than aorta (SMA EC50 0.8 ± 0.2 µM; aorta EC50 > 29.4 ± 4.4 µM), the mechanisms of acrolein-induced relaxation were studied in SMA. The potency of acrolein-induced relaxation was inhibited significantly by: 1) mechanically-impaired endothelium; 2) Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME); 3) guanylyl cyclase (GC) inhibitor (ODQ); and, 4) a TRPA1 antagonist (A967079). TRPA1 positive immunofluorescence was present in the endothelium. Compared with other known TRPA1 agonists, including allyl isothiocyanate (AITC), cinnamaldehyde, crotonaldehyde, and formaldehyde, acrolein stimulated a more potent TRPA1-dependent relaxation. Acrolein, at high concentration [100 µM], induced tension oscillations (spasms) independent of TRPA1 in precontracted SMA but not in aorta. In conclusion, acrolein is vasorelaxant at low levels (physiological) yet vasotoxic at high levels (toxicological).

Screening the Q-markers of TCMs from RA rat plasma using UHPLC-QTOF/MS technique for the comprehensive evaluation of Wu-Wei-Wen-Tong Capsule.

The appropriate selection of quality marker (Q-marker) for performing the comprehensive quality evaluation of traditional Chinese medicines (TCMs) has much more significance. Wu-Wei-Wen-Tong Capsule (WWWTC), a TCMs prescription, is mainly utilized to treat rheumatoid arthritis (RA) in China. However, the comprehensive quality control for WWWTC has not been achieved because of lacking system analysis for the Q-marker. In this study, a dual wavelength, 203 and 270 nm, was selected based on the feature of 15 Q-markers, and a reliable UHPLC-UV fingerprinting approach was established, achieving the comprehensive quality evaluation of WWWTC. First, we identified 91 prototypes in rat plasma after administering a set amount of WWWTC by using UHPLC-QTOF/MS technique and selected them as the candidate Q-markers. Next, based on the "five principles" of Q-marker selection, 15 absorbed components among them including coumarin, cinnamic acid, cinnamaldehyde, cinnamic alcohol, and 2-methoxycinnamaldehyde derived from Monarch medicine of Cmnamomi Mmulus; epimedin C, icariin, baohuoside I, and anhydroicaritin derived from Monarch medicine Epimedii Folium; germacrone, the sesquiterpene compound in Minister medicine Rhizoma Wenyujin Concisum; pachymic acid, the tetracyclic triterpenoid acids in Assistant medicine Poria; baicalin, baicalein, wogonin, and wogonoside in Guide medicine Scutellariae Radix, respectively, were seriously chosen as the Q-markers, indicating preferable pharmacological effect on RA, characterization of transitivity and traceability as well as measurable components in WWWTC. The effective and meaningful strategy displayed a unique perspective for the exploration of Q-markers in the quality evaluation and further ensured efficacy and safety of the TCMs.

Polyamine biomarkers as indicators of human disease.

The significant increase of periodontitis, chronic kidney disease (CKD), Alzheimer's disease and cancer can be attributed to an ageing population. Each disease produces a range of biomarkers that can be indicative of disease onset and progression. Biomarkers are defined as cellular (intra/extracellular components and whole cells), biochemical (metabolites, ions and toxins) or molecular (nucleic acids, proteins and lipids) alterations which are measurable in biological media such as human tissues, cells or fluids. An interesting group of biomarkers that merit further investigation are the polyamines. Polyamines are a group of molecules consisting of cadaverine, putrescine, spermine and spermidine and have been implicated in the development of a range of systemic diseases, in part due to their production in periodontitis. Cadaverine and putrescine within the periodontal environment have demonstrated cell signalling interfering abilities, by way of leukocyte migration disruption. The polyamines spermine and spermidine in tumour cells have been shown to inhibit cellular apoptosis, effectively prolonging tumorigenesis and continuation of cancer within the host. Polyamine degradation products such as acrolein have been shown to exacerbate renal damage in CKD patients. Thus, the use of such molecules has merit to be utilized in the early indication of such diseases in patients.

Plasma acrolein level in rheumatoid arthritis increases independently of the disease characteristics.

OBJECTIVE: This study aimed to clarify whether plasma acrolein level actually increases in rheumatoid arthritis (RA) patients, and to elucidate whether any relationship exists between the levels and the RA background variables. METHODS: Plasma levels of protein-conjugated acrolein (PC-Acro) in 84 patients (RA group) and 298 normal individuals (Control group) were measured by enzyme-linked immunosorbent assay procedures. The data were statistically analyzed with Wilcoxon rank-sum test, multiple logistic regression analyses and Spearman's rank correlation coefficient. RESULTS: The RA group showed significantly higher PC-Acro levels than the Control group (median [interquartile range]: 80.5 [63.2-105.2] and 65.9 [58.9-78.1] nmol/ml, respectively). Of background factors giving influence to PC-Acro level in the combination of the two groups, 'diagnosis of RA positive' indicated strong correlation to high PC-Acro level (odds ratio: 2.96; 95% confidence interval: 1.54-5.71). These increases of PC-Acro in the RA patients did not correlate to their disease duration and/or inflammatory variables: PC-Acro level could elevate even in early RA patients showing negative inflammatory findings. CONCLUSION: Plasma levels of PC-Acro increased with RA, but the levels did not correlate with RA background variables. This report provides the basis for further studies of early diagnosis of RA as well as its pathogenesis.

Assessing acrolein for determination of the severity of brain stroke, dementia, renal failure, and Sjögren's syndrome.

It was found recently that acrolein (CH2=CH-CHO), mainly produced from spermine, is more toxic than ROS (reactive oxygen species, O2-·, H2O2, and ·OH). In this review, we describe how the seriousness of brain infarction, dementia, renal failure, and SjÓ§gren's syndrome is correlated with acrolein. In brain infarction and dementia, it was possible to identify incipient patients with high sensitivity and specificity by measuring protein-conjugated acrolein (PC-Acro) in plasma together with IL-6 and CRP in brain infarction and Aß40/42 in dementia. The level of PC-Acro in plasma and saliva correlated with the seriousness of renal failure and SjÓ§gren's syndrome, respectively. Thus, development of acrolein scavenger medicines containing SH-group such as N-acetylcysteine derivatives is important to maintain QOL (quality of life) of the elderly.

The relationship between acrolein and oxidative stress in COPD: in systemic plasma and in local lung tissue.

Purpose: Cigarette smoke produces a high level of acrolein, which is thought to be pathogenically involved in the development of chronic obstructive pulmonary disease (COPD). The present study investigated the pathological role of acrolein in the development of COPD. Patients and methods: Acrolein concentration was measured in plasmas obtained from 47 patients with COPD and 18 current smokers without COPD, and in supernatants of homogenized lung tissues obtained from 10 never-smokers, 8 current smokers, and 8 patients with COPD by high-performance liquid chromatography. Oxidant status and antioxidant activity were measured using derivatives of reactive oxygen metabolite (d-ROM) and bio-antioxidant power (BAP), respectively, in the Free Radical Elective Evaluation FRAS4 system. In addition, immunohistochemistry was used to evaluate the over-presentation of acrolein in lung tissues of patients with COPD. Results: Plasma concentrations of acrolein were significantly higher in the patients with COPD than the non-COPD smokers (P<0.001), which significantly correlated with the oxidant status in patients with COPD (R=0.69, P<0.05). Similar pathological alterations in acrolein concentrations were found in the lung tissue supernatants of patients with COPD, which significantly correlated with the oxidant status in patients with COPD. Furthermore, acrolein was strongly expressed in the lung tissues of patients with COPD. Conclusion: The increased acrolein concentrations were highly involved in the pathogenesis of COPD through interference in the balance of oxidative stress versus antioxidant potentiality.

Exposure assessment of process-related contaminants in food by biomarker monitoring.

Exposure assessment is a fundamental part of the risk assessment paradigm, but can often present a number of challenges and uncertainties. This is especially the case for process contaminants formed during the processing, e.g. heating of food, since they are in part highly reactive and/or volatile, thus making exposure assessment by analysing contents in food unreliable. New approaches are therefore required to accurately assess consumer exposure and thus better inform the risk assessment. Such novel approaches may include the use of biomarkers, physiologically based kinetic (PBK) modelling-facilitated reverse dosimetry, and/or duplicate diet studies. This review focuses on the state of the art with respect to the use of biomarkers of exposure for the process contaminants acrylamide, 3-MCPD esters, glycidyl esters, furan and acrolein. From the overview presented, it becomes clear that the field of assessing human exposure to process-related contaminants in food by biomarker monitoring is promising and strongly developing. The current state of the art as well as the existing data gaps and challenges for the future were defined. They include (1) using PBK modelling and duplicate diet studies to establish, preferably in humans, correlations between external exposure and biomarkers; (2) elucidation of the possible endogenous formation of the process-related contaminants and the resulting biomarker levels; (3) the influence of inter-individual variations and how to include that in the biomarker-based exposure predictions; (4) the correction for confounding factors; (5) the value of the different biomarkers in relation to exposure scenario's and risk assessment, and (6) the possibilities of novel methodologies. In spite of these challenges it can be concluded that biomarker-based exposure assessment provides a unique opportunity to more accurately assess consumer exposure to process-related contaminants in food and thus to better inform risk assessment.

Acrolein toxicity at advanced age: present and future.

It is thought that tissue damage at advanced age is mainly caused by ROS (reactive oxygen species, O2-, H2O2, and ·OH). However, it was found that acrolein (CH2=CH-CHO) is more toxic than ROS, and is mainly produced from spermine (SPM), one of the polyamines, rather than from unsaturated fatty acids. Significant amounts of SPM are present normally as SPM-ribosome complexes, and contribute to protein synthesis. However, SPM was released from ribosomes due to the degradation of ribosomal RNA by ·OH or the binding of Ca2+ to ribosomes, and acrolein was produced from free SPM by polyamine oxidases, particularly by SPM oxidase. Acrolein inactivated several proteins such as GAPDH (glycelaldehyde-3-phosphate dehydrogenase), and also stimulated MMP-9 (matrix metalloproteinase-9) activity. Acrolein-conjugated GAPDH translocated to nucleus, and caused apoptosis like nitrosylated GAPDH. Through acrolein conjugation with several proteins, acrolein causes tissue damage during brain stroke, dementia, renal failure, and primary Sjögren's syndrome. Thus, development of acrolein scavengers with less side effects is very important to maintain QOL (quality of life) of elderly people.

Uremic toxins: some thoughts on acrolein and spermine.

Chronic kidney disease (CKD) is characterized by the progressive reduction of glomerular filtration rate and subsequent retention of organic waste compounds called uremic toxins. While patients with CKD are at a higher risk of premature death due to cardiovascular complications, this increased risk cannot be completely explained by classical cardiovascular risk factors such as hypertension, diabetes mellitus, and obesity. Instead, recent research suggests that uremic toxins may play a key role in explaining this marked increase in cardiovascular mortality in patients with CKD. While spermine, a tetra-amine, has previously been hypothesized to act as an uremic toxin, the following review presents a summary of recent literature that casts doubt on this assertion. Instead, acrolein, an oxidative product of spermine and the triamine spermidine, is likely responsible for the toxic effects previously attributed to spermine.

Simultaneous determination of cinnamaldehyde, cinnamic acid, and 2-methoxy cinnamic acid in rat whole blood after oral administration of volatile oil of Cinnamoni Ramulus by UHPLC-MS/MS: An application for a pharmacokinetic study.

A simple and rapid ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed for the simultaneous determination of cinnamaldehyde, cinnamic acid, and 2-methoxy cinnamic acid in rat whole blood. It was the first time to study the pharmacokinetics of 2-methoxy cinnamic acid in rat whole blood. Samples were processed by a one-step protein precipitation with acetonitrile-37% formaldehyde (90:10, v:v). Chromatographic separation was performed on a Thermo Scientific C18 column (2.1mm×50mm, 1.9µm) at room temperature. The total run time was 4min. The detection was accomplished by using positive and negative ion electrospray ionization in multiple reaction monitoring mode. The method was linear for all of the analytes over 1000 times concentration range with correlation coefficients greater than 0.99. The lower limits of quantification (LLOQ) were 0.1ng/mL for cinnamaldehyde, 5.8ng/mL for cinnamic acid, and 10ng/mL for 2-methoxy cinnamic acid, respectively. To our knowledge, this was the first time that the LLOQ for cinnamaldehyde in validated methods for biological samples was as low as 0.1ng/mL. Intra- and inter-day precision and accuracy were within ±9% for all of the analytes during the assay validation. Assay recoveries were higher than 80% and the matrix effects were minimal. The half-life were 8.7±0.7h for cinnamaldehyde, 1.0±0.5h for cinnamic acid, and 1.4±0.4h for 2-methoxy cinnamic acid, respectively. The validated assay was firstly applied to the simultaneous quantification of cinnamaldehyde, cinnamic acid, and 2-methoxy cinnamic acid, especially for 2-methoxy cinnamic acid in rat whole blood after oral administration of 15mg/kg essential oil of Cinnamoni Ramulus. It was observed that the Cmax and AUC of 2-methoxy cinnamic acid (0.01% in essential oil of Cinnamoni Ramulus) were greater than those of cinnamaldehyde (83.49% in essential oil of Cinnamoni Ramulus), which implied that 2-methoxy cinnamic acid might be the major bioactive constitutes in essential oil of Cinnamoni Ramulus.

Evaluation of dementia by acrolein, amyloid-ß and creatinine.

Plasma, urine and cerebrospinal fluid (CSF) were examined for biochemical markers of dementia. Protein-conjugated acrolein (PC-Acro) and the amyloid-ß (Aß)40/42 ratio in plasma can be used to detect mild cognitive impairment (MCI) and Alzheimer's disease (AD). In plasma, PC-Acro and the Aß40/42 ratio in MCI and AD were significantly higher relative to non-demented subjects. Furthermore, urine acrolein metabolite, 3-hydroxypropyl mercapturic acid (3-HPMA)/creatinine (Cre) and amino acid-conjugated acrolein (AC-Acro)/Cre in AD were significantly lower than MCI. It was also shown that reduced urine 3-HPMA/Cre correlated with increased plasma Aß40/42 ratio in dementia. The Aß40/PC-Acro ratio in CSF, together with Aß40 and Aß40/42 ratio, was lower in AD than MCI. Increased plasma PC-Acro and Aß40/42 ratio and decreased urine 3-HPMA/Cre correlated with cognitive ability (MMSE). These results indicate that the measurements of acrolein derivatives together with Aß and Cre in biologic fluids is useful to estimate severity of dementia.

Determination of acrolein in serum by high-performance liquid chromatography with fluorescence detection after pre-column fluorogenic derivatization using 1,2-diamino-4,5-dimethoxybenzene.

Acrolein is a major unsaturated aldehyde that is generated during the lipid peroxidation process. The measurement of acrolein in biological samples should be useful to estimate the degree of lipid peroxidation and to evaluate the effect of hazardous properties of acrolein on human health. In this study, a highly sensitive and selective high-performance liquid chromatography with fluorescence detection method was developed for the determination of acrolein in human serum. The proposed method involves the pre-column fluorogenic derivatization of acrolein with 1,2-diamino-4,5-dimethoxybenzene (DDB) as a reagent. The fluorescent derivative of acrolein could be detected clearly without any interfering reagent blank peaks because DDB does not have intrinsic fluorescence itself, and the detection limit was 10 nM (signal-to-noise ratio = 3). The proposed method could selectively detect acrolein in human serum with a simple protein precipitation treatment.

Relative risk values of age, acrolein, IL-6 and CRP as markers of periventricular hyperintensities: a cross-sectional study.

OBJECTIVE: Brain white matter hyperintensities can be divided into periventricular hyperintensity (PVH) and deep-and-subcortical white matter hyperintensity (DSWMH); the former contributes more to cognitive dysfunction and infarction risk. We conducted the present investigation to define the relationship between PVH and DSWMH. DESIGN: Cross-sectional study. SETTING: University hospital. PARTICIPANTS: We prospectively enrolled 228 healthy Japanese volunteers with relative risk values (RRVs) >0.5. PRIMARY OUTCOME MEASURES: We investigated whether it is possible to use the RRV to predict PVH and DSWMH. RESULTS: Among 228 volunteers, 103 (45.1%) and 157 (68.8%) exhibited PVH and DSWMH, respectively. Age, body mass index and PVH were significant independent determinants of RRV. A significant OR for PVH was noted in the highest RRV tertile compared with the lowest, after adjusting for potential confounding factors. A significant OR for high predicted PVH risk was found for RRV levels as well. CONCLUSIONS: Elevated RRV levels were significantly associated with increased predicted PVH, suggesting that measuring the plasma protein-conjugated acrolein, interleukin 6 and C reactive protein levels may be useful for identifying Japanese at high risk for PVH.

Simultaneous determination of four volatile compounds in rat plasma after oral administration of Shexiang Baoxin Pill (SBP) by HS-SPDE-GC-MS/MS and its application to pharmacokinetic studies.

In this study, a headspace, solid-phase dynamic extraction method coupled to gas chromatography-tandem mass spectrometry (HS-SPDE-GC-MS/MS) method was developed for the simultaneous determination of four volatile compounds, namely, isoborneol, borneol, muscone and cinnamaldehyde, in rat plasma after oral administration of Shexiang Baoxin Pill (SBP) using naphthalene as an internal standard (IS). The target compounds were extracted using an SPDE needle device coated with a poly (dimethylsiloxane) (PDMS) phase. The detection was achieved by GC-MS/MS in multiple reaction monitoring (MRM) mode. The optimised mass transition ion pairs (m/z) for quantitation were 95.1/67.1 for isoborneol and borneol, 85.0/67.0 for muscone, 131.0/77.0 for cinnamaldehyde and 128.1/102.1 for the IS. The parameters that affect the extraction ratio, such as the pre-incubation time, extraction temperature, number of extraction cycles, desorption volume and pH, were also optimised. The method was thoroughly validated with respect to specificity, linearity, precision, accuracy, recovery and stability. A sufficiently sensitive HS-SPDE-GC-MS/MS method was first developed in this study to determine the pharmacokinetics of volatile compounds found in rat plasma following oral administration of SBP. The method developed uses a simple procedure for plasma sample preparation and could be a promising tool for the analysis of complex volatile samples, such as traditional Chinese medicine (TCM).

Practical fluorescence detection of acrolein in human plasma via a two-step tethering approach.

Acrolein, a cytotoxic α,ß-unsaturated aldehyde and disease biomarker, was determined in plasma by means of a novel tethering strategy using Michael addition of the compound to a fluorescent dye, followed by immobilization of the product on microbeads via the aldehyde moiety. Elevation of blood acrolein was detected in mice treated with an anticancer agent cyclophosphamide, which releases acrolein upon activation. This method should be suitable for high-throughput diagnostic and clinical application.

Cigarette smoke induces systemic defects in cystic fibrosis transmembrane conductance regulator function.

RATIONALE: Several extrapulmonary disorders have been linked to cigarette smoking. Smoking is reported to cause cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction in the airway, and is also associated with pancreatitis, male infertility, and cachexia, features characteristic of cystic fibrosis and suggestive of an etiological role for CFTR. OBJECTIVES: To study the effect of cigarette smoke on extrapulmonary CFTR function. METHODS: Demographics, spirometry, exercise tolerance, symptom questionnaires, CFTR genetics, and sweat chloride analysis were obtained in smokers with and without chronic obstructive pulmonary disease (COPD). CFTR activity was measured by nasal potential difference in mice and by Ussing chamber electrophysiology in vitro. Serum acrolein levels were estimated with mass spectroscopy. MEASUREMENTS AND MAIN RESULTS: Healthy smokers (29.45 ± 13.90 mEq), smokers with COPD (31.89 ± 13.9 mEq), and former smokers with COPD (25.07 ± 10.92 mEq) had elevated sweat chloride levels compared with normal control subjects (14.5 ± 7.77 mEq), indicating reduced CFTR activity in a nonrespiratory organ. Intestinal current measurements also demonstrated a 65% decrease in CFTR function in smokers compared with never smokers. CFTR activity was decreased by 68% in normal human bronchial epithelial cells exposed to plasma from smokers, suggesting that one or more circulating agents could confer CFTR dysfunction. Cigarette smoke-exposed mice had decreased CFTR activity in intestinal epithelium (84.3 and 45%, after 5 and 17 wk, respectively). Acrolein, a component of cigarette smoke, was higher in smokers, blocked CFTR by inhibiting channel gating, and was attenuated by antioxidant N-acetylcysteine, a known scavenger of acrolein. CONCLUSIONS: Smoking causes systemic CFTR dysfunction. Acrolein present in cigarette smoke mediates CFTR defects in extrapulmonary tissues in smokers.

Reactive carbonyl compounds (RCCs) cause aggregation and dysfunction of fibrinogen.

Fibrinogen is a key protein involved in coagulation and its deposition on blood vessel walls plays an important role in the pathology of atherosclerosis. Although the causes of fibrinogen (fibrin) deposition have been studied in depth, little is known about the relationship between fibrinogen deposition and reactive carbonyl compounds (RCCs), compounds which are produced and released into the blood and react with plasma protein especially under conditions of oxidative stress and inflammation. Here, we investigated the effect of glycolaldehyde on the activity and deposition of fibrinogen compared with the common RCCs acrolein, methylglyoxal, glyoxal and malondialdehyde. At the same concentration (1 mmol/L), glycolaldehyde and acrolein had a stronger suppressive effect on fibrinogen activation than the other three RCCs. Fibrinogen aggregated when it was respectively incubated with glycolaldehyde and the other RCCs, as demonstrated by SDS-PAGE, electron microscopy and intrinsic fluorescence intensity measurements. Staining with Congo Red showed that glycolaldehyde- and acrolein-fibrinogen distinctly formed amyloid-like aggregations. Furthermore, the five RCCs, particularly glycolaldehyde and acrolein, delayed human plasma coagulation. Only glycolaldehyde showed a markedly suppressive effect on fibrinogenesis, none did the other four RCCs when their physiological blood concentrations were employyed, respectively. Taken together, it is glycolaldehyde that suppresses fibrinogenesis and induces protein aggregation most effectively, suggesting a putative pathological process for fibrinogen (fibrin) deposition in the blood.

Increased protein-conjugated acrolein and amyloid-ß40/42 ratio in plasma of patients with mild cognitive impairment and Alzheimer's disease.

The objective of this study was to determine whether plasma levels of acrolein, a compound that causes cell damage, and amyloid-ß (Aß) are useful biochemical markers for Alzheimer's disease (AD). The study included 221 elderly subjects divided into 101 non-demented [33 healthy control and 68 non-demented subjects with white matter hyperintensity (nd-WMH)], 50 mild cognitive impairment (MCI), and 70 AD. Increases in both protein-conjugated acrolein (PC-Acro) and Aß40/42 ratio were observed in MCI and AD patients compared with values in control subjects. When the combined measurements of PC-Acro and Aß40/42 ratio were evaluated using the median value of the relative risk value for dementia, they were in the order AD (0.98) ≥ MCI (0.97) > nd-WMH (0.83) > control (0.35). The results indicate that measurements of PC-Acro and Aß40/42 ratio not only detect MCI and AD patients but also nd-WMH subjects. Furthermore, both PC-Acro and Aß40/42 ratio in plasma for 120 MCI and AD patients were significantly higher than those for 101 control and nd-WMH subjects, indicating that both values become useful biochemical markers for MCI and AD subjects.

Protein-conjugated acrolein as a biochemical marker of brain infarction.

The relationship between acrolein (CH(2) =CH-CHO) and brain infarction is the focus of this review. It has been found that acrolein is produced mainly within cells from polyamines by polyamine oxidases (PAOs), especially from spermine by spermine oxidase during cell damage, and that acrolein is more toxic than reactive oxygen species (ROS) in a cell culture system. Thus, the possibility that acrolein and PAOs are good biochemical markers of stroke was tested because there are no other reliable biochemical markers at the early stage of stroke. Levels of protein-conjugated acrolein (PC-Acro) and PAOs (acrolein-producing enzymes) were significantly increased in the plasma of stroke patients. The multiplied value of PC-Acro by PAOs was nearly parallel with the size of stroke. Furthermore, when the combined measurements of PC-Acro, interleukin-6 (IL-6) and C-reactive protein (CRP) were evaluated along with age using a receiver operating characteristic (ROC) curve, even silent brain infarction (SBI), which is a small brain infarction, was indicated with approximately 84% sensitivity and specificity. These findings clearly indicate that acrolein is strongly correlated with cell damage during brain infarction.