Urinary Amino Acid-Conjugated Acrolein and Taurine as New Biomarkers for Detection of Dementia.

BACKGROUND: Dementia, including Alzheimer's disease (AD), is one of the serious diseases at advanced age, and its early detection is important for maintaining quality of life (QOL). OBJECTIVE: In this study, we sought novel biomarkers for dementia in urine. METHODS: Samples of urine were collected from 57 control subjects without dementia, 62 mild cognitive impairment (MCI) patients, and 42 AD patients. Mini-Mental State Examination (MMSE) was evaluated when subjects were examined by medical doctors. Urinary amino acid (lysine)-conjugated acrolein (AC-Acro) was measured using N ɛ-(3-formyl-3, 4-dehydropiperidine) lysine (FDP-Lys) ELISA kit, and taurine content was measured using a taurine assay kit. Values were normalized by creatinine content which was measured with the colorimetric assay kit. RESULTS: We found that urinary amino acid (lysine)-conjugated acrolein (AC-Acro) and taurine negatively correlated with MMSE score and are significantly lower in dementia patients compared to the normal subjects. When AC-Acro and taurine were evaluated together with age using an artificial neural network model, median relative risk values for subjects with AD, subjects with mild cognitive impairment, and control subjects were 0.96, 0.53, and 0.06, respectively. CONCLUSION: Since urine is relatively easy to collect, our findings provide a novel biomarker for dementia without invasiveness.

Time dependent transition of the levels of protein-conjugated acrolein (PC-Acro), IL-6 and CRP in plasma during stroke.

OBJECTIVE: Measurement of plasma levels of protein-conjugated acrolein (PC-Acro) together with IL-6 and CRP can be used to identify silent brain infarction (SBI) with high sensitivity and specificity. The aim of this study was to determine how these biomarkers vary during stroke. METHODS: Levels of PC-Acro, IL-6 and CRP in plasma were measured on day 0, 2, 7 and 14 after the onset of ischemic or hemorrhagic stroke. RESULTS: After the onset of stroke, the level of PC-Acro in plasma was elevated corresponding to the size of stroke. It returned to near control levels by day 2, and remained similar through day 14. The degree of the decrease in PC-Acro on day 2 was greater when the size of brain infarction or hemorrhage was larger. An increase in IL-6 and CRP occurred after the increase in PC-Acro, and it was well correlated with the size of the injury following infarction or hemorrhage. The results suggest that acrolein becomes a trigger for the production of IL-6 and CRP, as previously observed in a mouse model of stroke and in cell culture systems. The increase in IL-6 and CRP was also correlated with poor outcome judging from mRS. CONCLUSION: The results indicate that the degree of the decrease in PC-Acro and the increase in IL-6 and CRP from day 0 to day 2 was correlated with the size of brain infarction, and the increase in IL-6 and CRP with poor outcome at discharge.

Correlation between brain damage, associated biomarkers, and medication in psychiatric inpatients: A cross-sectional study.

BACKGROUND: We clarified the correlation between brain damage, associated biomarkers and medication in psychiatric patients, because patients with schizophrenia have an increased risk of stroke. METHODS: The cross-sectional study was performed from January 2013 to December 2015. Study participants were 96 hospitalized patients (41 men and 55 women) in the Department of Psychiatry at Kohnodai Hospital, National Center for Global Health and Medicine, Ichikawa, Chiba, Japan. Patients were classified into schizophrenia (n=70) and mood disorders (n=26) by psychiatric diagnoses with DSM-IV-TR criteria. RESULTS: The incidence of brain damage [symptomatic and silent brain infarctions (SBIs) and white matter hyperintensity (WMH)] was correlated more with mood disorders than with schizophrenia. It has been previously shown that the concentrations of protein-conjugated acrolein (PC-Acro) and interleukin-6 (IL-6) increased in plasma of brain infarction patients together with C-reactive protein (CRP). The concentration of PC-Acro was significantly higher in patients with mood disorders than in those with schizophrenia. The concentration of IL-6 in both groups was nearly equal to that in the control group, but that of CRP in both groups, especially in mood disorders, was higher than that in the control group. Accordingly, the relative risk value for brain infarction was higher in patients with mood disorders than with schizophrenia. Medication with atypical antipsychotics reduced PC-Acro significantly in all psychiatric patients and reduced IL-6 in mood disorder patients. CONCLUSION: Measurement of 3 biomarkers (CRP, PC-Acro and IL-6) are probably useful for judgement of severity of brain damage and effectiveness of medication in psychiatric patients.

Distinguishing mild cognitive impairment from Alzheimer's disease with acrolein metabolites and creatinine in urine.

BACKGROUND: We previously reported that the level of urinary 3-hydroxypropyl mercapturic acid (3-HPMA)/creatinine (Cre) was reduced following stroke. The aim of this study was to determine whether the level of 3-HPMA/Cre in urine was reduced in subjects with dementia. METHODS: The level of 3-HPMA was measured by LC-MS/MS, and that of amino acid conjugated acrolein (AC-Acro) was by ELISA. The study included 128 elderly subjects divided into 74 non-demented (control), 22 mild cognitive impairment (MCI) and 32 Alzheimer's disease (AD) subjects. RESULTS: The urinary 3-HPMA/Cre and AC-Acro/Cre in MCI plus AD subjects were significantly lower than those in control subjects. In addition, urinary Cre in AD subjects was significantly higher than that in MCI subjects, and 3-HPMA/Cre and AC-Acro/Cre in AD subjects were significantly lower than that in MCI subjects. Among these three markers, the lower 3-HPMA/Cre ratio was most strongly correlated with the decline of MMSE (Mini-Mental State Examination) and the increase in CDRsob (Clinical Dementia Rating Scale Sum of Boxes Scores). Furthermore, reduction in 3-HPMA/Cre in urine was well correlated with increase in Aß40/42 in plasma in demented subjects. CONCLUSION: The results indicate that 3-HPMA/Cre in urine is the most reliable biochemical marker to distinguish AD subjects from MCI subjects among three markers.

Distinction between mild cognitive impairment and Alzheimer's disease by CSF amyloid ß40 and ß42, and protein-conjugated acrolein.

BACKGROUND: We found previously that the amyloid ß40/42 (Aß40/42) ratio and the level of protein-conjugated acrolein (PC-Acro) in plasma were increased in mild cognitive impairment (MCI) and Alzheimer's disease (AD) subjects. We determined whether MCI and AD subjects can be differentiated based on the levels of Aß40, Aß42, and PC-Acro in cerebrospinal fluid (CSF). METHODS: Aß40, Aß42, PC-Acro, Tau and phosphorylated Tau in CSF were measured by ELISA. RESULTS: Median values of Aß40, Aß40/PC-Acro and Aß40/42 in CSF were significantly lower in 54 AD subjects than those in 40 MCI subjects. Severity of VOI (volume of interest) atrophy was most intensely correlated with the decrease in Aß40/PC-Acro and then that in Aß40 and Aß42/PC-Acro. MMSE was most intensely correlated with the decrease in Aß42 and Aß40, and then that in Aß42/PC-Acro and Aß40/PC-Acro. CONCLUSION: A decrease in Aß40/PC-Acro in CSF is well correlated with brain damage, and a decrease in Aß42 and Aß40 is well correlated with cognitive ability. Measurement of PC-Acro together with Aß40 and Aß42 provides a more precise evaluation of severity of AD subjects.

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.

Inverse correlation between stroke and urinary 3-hydroxypropyl mercapturic acid, an acrolein-glutathione metabolite.

BACKGROUND: We found previously that increases in plasma levels of protein-conjugated acrolein and polyamine oxidases, enzymes that produce acrolein, are good biomarkers for stroke. The aim of this study was to test whether 3-hydroxypropyl mercapturic acid (3-HPMA), an acrolein-glutathione metabolite, was increased in the urine of stroke patients. METHODS: The level of 3-HPMA in urine was measured by liquid chromatography with tandem mass spectrometry (LC-MS/MS). Stroke (78 subjects) was divided into 52 cerebral infarction (CI) and 26 cerebral hemorrhage (CH) on the basis of clinical information including brain imaging. RESULTS: A major acrolein derivative in urine is 3-HPMA. Being different from the results of PC-Acro in plasma, 3-HPMA in urine decreased following stroke. The median value of µmol 3-HPMA/g creatinine (Cre) for 90 control subjects was 2.83, while that for 78 stroke patients was 1.56. The degree of the decrease in 3-HPMA was similar in both CI and CH patients. Furthermore, the median value of µmol 3-HPMA/g Cre in 56 patients with lesions ≥ 1cm in diameter (1.39) was significantly lower than that in 20 patients with lesion <1cm in diameter (2.16). CONCLUSION: Inverse correlation between stroke and urinary 3-HPMA was observed. The results suggest that stroke is aggravated when nervous system tissues have a reduced level of glutathione.

Relationship between metabolic disorders and relative risk values of brain infarction estimated by protein-conjugated acrolein, IL-6 and CRP together with age.

BACKGROUND: We have recently found that the median relative risk value (RRV) (0-1) of brain infarction estimated by protein-conjugated acrolein (PC-Acro), IL-6 and CRP together with age was in the order silent brain infarction (SBI) (0.80)>carotid atherosclerosis (CA) (0.76)>white matter hyperintensity (WMH) (0.46)>control (0.14). We clarified how metabolic disorders [hypertension (HT), hyperlipidemia (HL) and hyperglycemia (HG)] are correlated with RRV. METHODS: The levels of PC-Acro, IL-6 and CRP in plasma were measured by ELISA. SBI and WMH were evaluated by MRI, and CA was evaluated by duplex carotid ultrasonography. RESULTS: The median RRV of metabolic disorders was in the order HT+HG (0.84)>HT+HL (0.73)>HT (0.65)≈HG (0.65)>HL (0.61)>HL+HG (0.48)>no metabolic disorder (0.24)>normal (0.11). Correlation with SBI was in the order HT+HG (52%)>HT+HL (42%)>HT (40%)>HG (34%)≈HL(33%)>HL+HG (14%)≈no metabolic disorder (14%). CONCLUSION: The results indicate that HT is the most strongly associated factor with SBI among metabolic disorders and that the seriousness of metabolic disorder estimated by RRV was well correlated with SBI.

Correlation between images of silent brain infarction, carotid atherosclerosis and white matter hyperintensity, and plasma levels of acrolein, IL-6 and CRP.

OBJECTIVE: We found previously that the measurement of plasma levels of protein-conjugated acrolein (PC-Acro) together with IL-6 and CRP can be used to identify silent brain infarction (SBI) with high sensitivity and specificity. The aim of this study was to clarify how three biochemical markers are correlated to SBI, carotid atherosclerosis (CA) and white matter hyperintensity (WMH). METHODS: The levels of PC-Acro, IL-6 and CRP in plasma were measured by ELISA. SBI and WMH were evaluated by MRI, and CA was evaluated by duplex carotid ultrasonography. RESULTS: A total of 790 apparently healthy volunteers were classified into 260 control, 214 SBI, 263 CA and 245 WMH subjects, which included 187 subjects with two or three pathologies. When the combined measurements of PC-Acro, IL-6 and CRP were evaluated together with age, using a receiver operating characteristic curve and artificial neural networks, the relative risk value (RRV), an indicator of tissue damage, was in the order SBI with CA (0.90)>SBI (0.80)>CA (0.76)>WMH with CA (0.65)>WMH (0.46)>control (0.14). RRV was also correlated with severity in each group of SBI, CA and WMH. CONCLUSION: The RRV supports the idea that the degree of risk to develop a stroke is in the order SBI>CA>WMH.

Dimethylarsine likely acts as a mouse-pulmonary tumor initiator via the production of dimethylarsine radical and/or its peroxy radical.

AIMS: Recent animal experiments have indicated that dimethylarsinic acid (DMA), a main metabolite of inorganic arsenic, is a complete carcinogen in the lung of mice and the urinary bladder of rats, nevertheless, no ultimate-active metabolite from DMA has been identified thus far. We have proposed that dimethylarsine ((CH(3))(2)AsH), an ultimate reductive metabolite of DMA, is excreted in the expired air of mice administered DMA, and furthermore, was easily converted into dimethylarsine radical ((CH(3))(2)As*) and dimethylarsine peroxy radical ((CH(3))(2)AsOO*) by its reaction with O(2). The aim of the present study was to elucidate the possible mode of the tumorigenic action by dimethylated arsenic. MAIN METHODS: In vitro experiments using GSH reductase as a two-electron donor of dimethylarsenic-glutathione conjugate ((CH(3))(2)As-SG) and DNA adduct assay via a photochemical approach were performed. A lung tumorigenicity assay of (CH(3))(2)AsH suspended in argon-atmospheric olive oil for 5 days was also conducted in mice. KEY FINDINGS: The results indicated that (CH(3))(2)AsH was easily produced enzymatically from (CH(3))(2)As-SG and showed tumor-initiating action in mouse lung via the production of (CH(3))(2)As* and (CH(3))(2)AsOO* by its reaction with O(2), and that these radicals have the ability to form DNA adducts. SIGNIFICANCE: The carcinogenicity of DMA, at least in mouse lung, could be explained based on the proposal that oral administration of DMA induces pulmonary tumors in mice, and arises from the arsine radicals produced through (CH(3))(2)AsH, which was enzymatically reduced from (CH(3))(2)As-SG.

Dimethylarsine likely acts as a mouse-pulmonary tumor initiator via the production of dimethylarsine radical and/or its peroxy radical.

AIMS: Recent animal experiments have indicated that dimethylarsinic acid (DMA), a main metabolite of inorganic arsenic, is a complete carcinogen in the lung of mice and the urinary bladder of rats, nevertheless, no ultimate-active metabolite from DMA has been identified thus far. We have proposed that dimethylarsine ((CH3)2AsH), an ultimate reductive metabolite of DMA, is excreted in the expired air of mice administered DMA, and furthermore, was easily converted into dimethylarsine radical ((CH3)2As•) and dimethylarsine peroxy radical ((CH3)2AsOO•) by its reaction with O2. The aim of the present study was to elucidate the possible mode of the tumorigenic action by dimethylated arsenic. MAIN METHODS: In vitro experiments using GSH reductase as a two-electron donor of dimethylarsenic-glutathione conjugate ((CH3)2As-SG) and DNA adduct assay via a photochemical approach were performed. A lung tumorigenicity assay of (CH3)2AsH suspended in argon-atmospheric olive oil for 5 days was also conducted in mice. KEY FINDINGS: The results indicated that (CH3)2AsH was easily produced enzymatically from (CH3)2As-SG and showed tumor-initiating action in mouse lung via the production of (CH3)2As• and (CH3)2AsOO• by its reaction with O2, and that these radicals have the ability to form DNA adducts. SIGNIFICANCE: The carcinogenicity of DMA, at least in mouse lung, could be explained based on the proposal that oral administration of DMA induces pulmonary tumors in mice, and arises from the arsine radicals produced through (CH3)2AsH, which was enzymatically reduced from (CH3)2As-SG.

Oral administration of diphenylarsinic acid, a degradation product of chemical warfare agents, induces oxidative and nitrosative stress in cerebellar Purkinje cells.

A new clinical syndrome with prominent cerebellar symptoms in patients living in Kamisu City, Ibaraki Prefecture, Japan, is described. Since the patients ingested drinking water containing diphenylarsinic acid (DPA), a stable degradation product of both diphenylcyanoarsine and diphenylchloroarsine, which were developed for use as chemical weapons and cause severe vomiting and sneezing, DPA was suspected of being responsible for the clinical syndrome. The purpose of the present study was to elucidate prominent cerebellar symptoms due to DPA. The aim of the study was to determine if single (15 mg/kg) or continuous (5 mg/kg/day for 5 weeks) oral administration of DPA to ICR-strain mice induced oxidative and/or nitrosative stress in their brain. Significantly positive staining with malondialdehyde (MDA) and 3-nitrotyrosine (3-NT) was observed in the cerebellar Purkinje cells by repeated administration (5 mg/kg/day) with DPA for 5 weeks that led to the cerebellar symptoms from a behavioral pharmacology standpoint and by single administration of DPA (15 mg/kg). Furthermore, it is possible that the production of 3-NT was not caused by peroxynitrite formation. The present results suggest the possibility that arsenic-associated novel active species may be a factor underlying the oxidative and nitrosative stress in Purkinje cells due to exposure to DPA, and that the damage may lead to the cerebellar symptoms.

The role of trivalent dimethylated arsenic in dimethylarsinic acid-promoted skin and lung tumorigenesis in mice: tumor-promoting action through the induction of oxidative stress.

We investigated the relationship between lung- and skin-tumor promotion and oxidative stress caused by administration of dimethylarsinic acid (DMA(V)) in mice. The incidence of lung tumors induced by lung tumor initiator (4NQO) and DMA(V) were, as well as 8-oxo-2'-deoxyguanosine (8-oxodG), suppressed by cotreatment with (-)epigallocatechin gallate (EGCG). When mice were topically treated with trivalent dimethylated arsenic (DMA(III)), a further reductive metabolite of DMA(V), not only an increase in skin tumors but also an elevation of 8-oxodG in epidermis were observed. These results suggest that tumor promotion due to DMA(V) administration is mediated by DMA(III) through the induction of oxidative stress.

The role of active arsenic species produced by metabolic reduction of dimethylarsinic acid in genotoxicity and tumorigenesis.

In recent research of arsenic carcinogenesis, many researchers have directed their attention to methylated metabolites of inorganic arsenics. Because of its high cytotoxicity and genotoxicity, trivalent dimethylated arsenic, which can be produced by the metabolic reduction of dimethylarsinic acid (DMA), has attracted considerable attention from the standpoint of arsenic carcinogenesis. In the present paper, we examined trivalent dimethylated arsenic and its further metabolites for their chemical properties and biological behavior such as genotoxicity and tumorigenicity. Our in vitro and in vivo experiments suggested that the formation of cis-thymine glycol in DNA was induced via the production of dimethylated arsenic peroxide by the reaction of trivalent dimethylated arsenic with molecular oxygen, but not via the production of common reactive oxygen species (ROS; superoxide, hydrogen peroxide, hydroxyl radical, etc.). Thus, dimethylated arsenic peroxide may be the main species responsible for the tumor promotion in skin tumorigenesis induced by exposure to DMA. Free radical species, such as dimethylarsenic radical [(CH(3))(2)As.] and dimethylarsenic peroxy radical [(CH(3))(2)AsOO.], that are produced by the reaction of molecular oxygen and dimethylarsine [(CH(3))(2)AsH], which is probably a further reductive metabolite of trivalent dimethylated arsenic, may be main agents for initiation in mouse lung tumorigenesis.

Oxidative DNA damage following exposure to dimethylarsinous iodide: the formation of cis-thymine glycol.

The purpose of the present study was to elucidate the genotoxic mechanism of trivalent dimethylated arsenic, particularly the induction mechanism of oxidative stress in nuclear bases. Cis-thymine glycol was used as a biomarker of DNA oxidation damage. The treatment of thymine with dimethylarsinous iodide (DMI), a model compound of dimethylarsinous acid, induced the formation of cis-thymine glycol. This oxidative damage was induced via the production of dimethylated arsenic peroxide, but not via the production of superoxide anion or hydrogen peroxide. Trivalent dimethylated arsenic may thus play an important role in arsenic carcinogenesis through the induction of oxidative base damage.