Potential Antioxidative Activity of Homocysteine in Erythrocytes under Oxidative Stress.

Homocysteine is an amino acid containing a free sulfhydryl group, making it probably contribute to the antioxidative capacity in the body. We recently found that plasma total homocysteine (total-Hcy) concentration increased with time when whole blood samples were kept at room temperature. The present study was to elucidate how increased plasma total-Hcy is produced and explore the potential physiological role of homocysteine. Erythrocytes and leukocytes were separated and incubated in vitro; the amount of total-Hcy released by these two kinds of cells was then determined by HPLC-MS. The effects of homocysteine and methionine on reactive oxygen species (ROS) production, osmotic fragility, and methemoglobin formation in erythrocytes under oxidative stress were studied. The reducing activities of homocysteine and methionine were tested by ferryl hemoglobin (Hb) decay assay. As a result, it was discovered that erythrocytes metabolized methionine to homocysteine, which was then oxidized within the cells and released to the plasma. Homocysteine and its precursor methionine could significantly decrease Rosup-induced ROS production in erythrocytes and inhibit Rosup-induced erythrocyte's osmotic fragility increase and methemoglobin formation. Homocysteine (but not methionine) was demonstrated to enhance ferryl Hb reduction. In conclusion, erythrocytes metabolize methionine to homocysteine, which contributes to the antioxidative capability under oxidative stress and might be a supplementary protective factor for erythrocytes against ROS damage.

Comparing the Effect of Piperine and Ilepcimide on the Pharmacokinetics of Curcumin in SD Rats.

The poor bioavailability and rapid metabolism of curcumin (CUR) restrict its clinical application. Piperine (PIP), which was extracted from natural compounds, can increase the plasma concentration of curcumin in humanidad. As an artificial synthetic piperine analog, silepcimide (ILE) has significant advantages because of the low price and simple synthesis process. In this study, a simple and rapid HPLC-UV method was developed for determination of the plasma concentration of CUR, PIP,ILE and dihydrocurcumin (DHC, a metabolite of CUR) simultaneously. Meanwhile, the effects of PIP and ILE on the plasma concentration and pharmacokinetics of DHC in SD rats was studied to explore whether ILE could serve as a CUR bioavailability enhancer. The metabolic pathway of CUR was studied by comparing the differences of CUR plasma concentration between intravenous injection and oral administration over the same time period, and reacting with small intestine homogenate without microbes of SD rats. The results of drug-time curve showed that combined administration of ILE and CUR had significant effect on plasma concentrations of DHC. Repeated administration of PIP or ILE could significantly increase the plasma concentration of DHC. Plasma CUR could be detected in the samples of from intravenous injection of CUR rats, whereas, it couldn't be detected in the plasma sample form oral administration rats. CUR incubated with intestinal homogenate without intestinal bacteria could not be transformed into DHC. In conclusion, our results show that ILE can improve the bioavailability of CUR. Additionally, it was inferred that most of the CUR was reduced to DHC by NADPH when it was absorbed from gastrointestinal tract, and our results demonstrated that this pathway might be mediated by gastrointestinal microorganisms.

Degradation of FA reduces Aß neurotoxicity and Alzheimer-related phenotypes.

Dysregulation of formaldehyde (FA) has been implicated in the development of Alzheimer's Disease (AD). Elevated FA levels in Alzheimer's patients and animal models are associated with impaired cognitive functions. However, the exact role of FA in AD remains unknown. We now identified that oxidative demethylation at serine8/26 of amyloid-beta protein (Aß) induced FA generation and FA cross-linked with the lysine28 residue in the ß-turn of Aß monomer to form Aß dimers, and then accelerated Aß oligomerization and fibrillogenesis in vitro. However, Aß42 mutation in serine8/26, lysine28 abolished Aß self-aggregation. Furthermore, Aß inhibited the activity of formaldehyde dehydrogenase (FDH), the enzyme for FA degradation, resulting in FA accumulation. In turn, excess of FA stimulated Aß aggregation both in vitro and in vivo by increasing the formation of Aß oligomers and fibrils. We found that degradation of FA by formaldehyde scavenger-NaHSO3 or coenzyme Q10 reduced Aß aggregation and ameliorated the neurotoxicity, and improved the cognitive performance in APP/PS1 mice. Our study provides evidence that endogenous FA is essential for Aß self-aggregation and scavenging FA could be an effective strategy for treating AD.

Larger endothelium-dependent contractions in iliac arteries of adult SHRs are attributed to differential downregulation of TP and EP3 receptors in the vessels of WKYs and SHRs during the transition from adolescence to adulthood.

This study was to determine how endothelium-dependent contractions (EDCs) change in iliac arteries of Wistar-Kyoto (WKYs) and spontaneously hypertensive rats (SHRs) during the transition from adolescence to adulthood and the underlying mechanism(s). We also aimed to elucidate effects of L-798106, an EP3 receptor antagonist, on EDCs and the blood pressure increase in adolescent SHRs. Blood vessels were isolated for functional and biochemical analyses. EDCs were comparable in adolescent iliac arteries of both strains, and contractions to ACh, prostacyclin (PGI2), the EP3 receptor agonist sulprostone and the TP receptor agonist U46619 in adult vessels were less prominent compared with those in the adolescents, while the attenuation of vasoconstrictions to ACh, PGI2 or U46619 with age was to a lesser extent in SHRs. PGI2 production was decreased to a similar level in adult arteries. TP and EP3 expressions were downregulated in adult vessels, whereas the extent of TP downregulation was less in SHRs. L-798106 partially suppressed the vasoconstrictions to U46619 and attenuated EDCs to a greater extent than SQ29548, and administration of L-798106 blunted the blood pressure increase with age in prehypertensive SHRs. These results demonstrate the comparable EDCs in iliac arteries of the adolescents are decreased in the adults, but relatively larger EDCs in adult SHRs can be a reflection of differential downregulation of TP and EP3 receptors during the transition from adolescence to adulthood. Also, our data suggest that blockade of both TP and EP3 receptors starting from the prehypertensive stage suppresses EDCs and the development of hypertension in SHRs.

Determination of plasma homocysteine with a UHPLC-MS/MS method: Application to analyze the correlation between plasma homocysteine and whole blood 5-methyltetrahydrofolate in healthy volunteers.

An ultra-high performance liquid chromatography tandem mass spectrometry method was developed for determination of homocysteine (HCY) in human plasma. The HCY was derivatized with 2-chloro-1-methylquinolinium tetrafluoroborate and isolated using solid-phase extraction. Derivatization, isolation and detection procedures were optimized. Satisfactory linearity was obtained with determination coefficients (r2 ) >0.999. The intra- and inter-day precisions were in the interval of 1.2-5.1% and accuracy was within ±7%. Mean recoveries were close to 100%. The limit of detection and the limit of quantification were 0.46 and 1.38 µmol/L, respectively. The method was then applied to investigate the relationship between plasma HCY and whole blood 5-methyltetrahydrofolate levels in healthy volunteers. The results revealed that the plasma level of HCY was significantly negatively correlated to whole blood 5-methyltetrahydrofolate in volunteers.

New insight into Alzheimer's disease: Light reverses Aß-obstructed interstitial fluid flow and ameliorates memory decline in APP/PS1 mice.

INTRODUCTION: Pharmacological therapies to treat Alzheimer's disease (AD) targeting "Aß" have failed for over 100 years. Low levels of laser light can disassemble Aß. In this study, we investigated the mechanisms that Aß-blocked extracellular space (ECS) induces memory disorders in APP/PS1 transgenic mice and addressed whether red light (RL) at 630 nm rescues cognitive decline by reducing Aß-disturbed flow of interstitial fluid (ISF). METHODS: We compared the heating effects on the brains of rats illuminated with laser light at 630, 680, and 810 nm for 40 minutes, respectively. Then, a light-emitting diode with red light at 630 nm (LED-RL) was selected to illuminate AD mice. The changes in the structure of ECS in the cortex were examined by fluorescent double labeling. The volumes of ECS and flow speed of ISF were quantified by magnetic resonance imaging. Spatial memory behaviors in mice were evaluated by the Morris water maze. Then, the brains were sampled for biochemical analysis. RESULTS: RL at 630 nm had the least heating effects than other wavelengths associated with ~49% penetration ratio into the brains. For the molecular mechanisms, Aß could induce formaldehyde (FA) accumulation by inactivating FA dehydrogenase. Unexpectedly, in turn, FA accelerated Aß deposition in the ECS. However, LED-RL treatment not only directly destroyed Aß assembly in vitro and in vivo but also activated FA dehydrogenase to degrade FA and attenuated FA-facilitated Aß aggregation. Subsequently, LED-RL markedly smashed Aß deposition in the ECS, recovered the flow of ISF, and rescued cognitive functions in AD mice. DISCUSSION: Aß-obstructed ISF flow is the direct reason for the failure of the developed medicine delivery from superficial into the deep brain in the treatment of AD. The phototherapy of LED-RL improves memory by reducing Aß-blocked ECS and suggests that it is a promising noninvasive approach to treat AD.

Synthesis and Evaluation of Pyridoxal Hydrazone and Acylhydrazone Compounds as Potential Angiogenesis Inhibitors.

BACKGROUND/AIMS: Hydrazone and acylhydrazone derivatives, which are produced from aldehyde reacting with hydrazine or acylhydrazine, have been reported to exhibit antitumor activities. However, the angionenic effects of this kind of derivatives haven't been elucidated. Here, we synthesized 12 pyridoxal hydrazone and acylhydrazone compounds and investigated their antiangiogenic effects and the underlying mechanisms. METHOD: 3-(4,5-Dimethylthiazol-2-yl)-2, 5-dipheyltetrazolium bromide assay was used to screen the inhibitory effects of the synthesized compounds on endothelial cells (ECs) proliferation. The compound with best inhibitory effect was further evaluated with wound-healing assay and tube formation assay. Calcein-Am assay was carried out to determine the content of intracellular labile iron pool (LIP). Intracellular reduced glutathione (GSH) was determined by spectrophotometry. Flow cytometry was used to determine cell cycle and apoptosis. RESULTS: Compound 10 (3-hydroxy-5-[hydroxymethyl]-2-methyl-pyridine-4-carbaldehyde-2-naphthalen-1-acetyl hydrazone) showed the best inhibitory effect on human umbilical vascular ECs proliferation, with IC50 value of 25.4 µmol/L. It not only inhibited wound-healing and tube formation of ECs, but also decreased the content of intracellular LIP and GSH. Furthermore, it arrested ECs cycle at S phase and induced cell apoptosis. CONCLUSIONS: Compound 10 exhibits antiangiogenic effects by reducing the content of intracellular LIP and GSH, and subsequently arresting cell cycle and inducing cell apoptosis.

Illumination with 630 nm Red Light Reduces Oxidative Stress and Restores Memory by Photo-Activating Catalase and Formaldehyde Dehydrogenase in SAMP8 Mice.

AIMS: Pharmacological treatments for Alzheimer's disease (AD) have not resulted in desirable clinical efficacy over 100 years. Hydrogen peroxide (H2O2), a reactive and the most stable compound of reactive oxygen species, contributes to oxidative stress in AD patients. In this study, we designed a medical device to emit red light at 630 ± 15 nm from a light-emitting diode (LED-RL) and investigated whether the LED-RL reduces brain H2O2 levels and improves memory in senescence-accelerated prone 8 mouse (SAMP8) model of age-related dementia. RESULTS: We found that age-associated H2O2 directly inhibited formaldehyde dehydrogenase (FDH). FDH inactivity and semicarbazide-sensitive amine oxidase (SSAO) disorder resulted in endogenous formaldehyde (FA) accumulation. Unexpectedly, excess FA, in turn, caused acetylcholine (Ach) deficiency by inhibiting choline acetyltransferase (ChAT) activity in vitro and in vivo. Interestingly, the 630 nm red light can penetrate the skull and the abdomen with light penetration rates of ∼49% and ∼43%, respectively. Illumination with LED-RL markedly activated both catalase and FDH in the brains, cultured cells, and purified protein solutions, all reduced brain H2O2 and FA levels and restored brain Ach contents. Consequently, LED-RL not only prevented early-stage memory decline but also rescued late-stage memory deficits in SAMP8 mice. INNOVATION: We developed a phototherapeutic device with 630 nm red light, and this LED-RL reduced brain H2O2 levels and reversed age-related memory disorders. CONCLUSIONS: The phototherapy of LED-RL has low photo toxicity and high rate of tissue penetration and noninvasively reverses aging-associated cognitive decline. This finding opens a promising opportunity to translate LED-RL into clinical treatment for patients with dementia. Antioxid. Redox Signal. 00, 000-000.

TP and/or EP3 receptors mediate the vasoconstrictor and pressor responses of prostaglandin F2α in mice and/or humans.

The vasoconstrictor and/or pressor effects of prostaglandin (PG)F2α participate in the development of vascular pathologies and limit the clinical use of the agent. This study aimed to determine the receptor types responsible for the vasoconstrictor activity of PGF2α and whether they mediate the pressor response evoked by the prostanoid under in vivo conditions. Experiments were performed on genetically altered mice and/or on vessels from these mice or humans. Here we show that deletion of the thromboxane-prostanoid receptor (TP-/-) abolished or drastically diminished the contraction to PGF2α in isolated mouse vessels (some of which were resistance arteries) and reduced the elevation in blood pressure evoked by the prostanoid under in vivo conditions. In accordance, TP antagonism abolished the contraction in small arteries of human omentum. Further deletion of E prostanoid receptor type 3 (EP3-/-) removed the PGF2α-evoked contraction that remained in some TP-/- arteries and added to the effect of TP-/- on the elevation in blood pressure evoked by the prostanoid under in vivo conditions. In contrast, the uterine contraction to PGF2α mediated via the F prostanoid receptor (FP) was unaltered in TP-/-/EP3-/- mice. These results demonstrate that the non-FP receptors TP and/or EP3 mediate the vasoconstrictor and pressor effects of PGF2α, which are still of concern under clinical conditions.-Liu, B., Li, J., Yan, H., Tian, D., Li, H., Zhang, Y., Guo, T., Wu, X., Luo, W., Zhou, Y. TP and/or EP3 receptors mediate the vasoconstrictor and pressor responses of prostaglandin F2α in mice and/or humans.

A rapid and sensitive fluorescence method for detecting urine formaldehyde in patients with Alzheimer's disease.

BACKGROUND: Morning urine formaldehyde concentrations could predict the severe degree of dementia in patients with post-stroke dementia and Alzheimer's disease. However, the routinely available technique of high-performance liquid chromatography (HPLC) for detecting urine formaldehyde requires expensive and sophisticated equipment. METHODS: We established a fluorescence spectrophotometric method by using a formaldehyde-specific fluorescent probe-NaFA (λex/em = 430/543 nm). As a standard reference method, the same batch of urine samples was analysed by HPLC with a fluorescence detector (λex/em = 346/422 nm). Then we compared the limits of detection and the limits of quantization detected by these two methods and addressed the relationship between urine formaldehyde and human cognitive ability. The Mini-Mental State Examination (MMSE), Clinical Dementia Rating and Activities of Daily Living scale were used to evaluate cognition function in 30 Alzheimer's disease patients and 52 healthy age-matched controls. RESULTS: Limits of detection and limits of quantization (1.27 and 2.48 µM) of the NaFA probe method were more accurate than Fluo-HPLC (1.52 and 2.91 µM). There was no difference in the detected formaldehyde values within day and day-to-day. Notably, only 3/82 urine formaldehyde concentrations detected by NaFA probe were below zero, while 12/82 of the values analysed by Fluo-HPLC were abnormal. More importantly, there were negatively correlated between urine formaldehyde concentrations detected by NaFA probe and MMSE scores, but positively correlated with Clinical Dementia Rating scores in Alzheimer's disease patients. CONCLUSIONS: This detecting urine formaldehyde method by NaFA probe was more rapid, sensitive and accurate than Fluo-HPLC.

Prostaglandin D2 evokes potent uterine contraction via the F prostanoid receptor in postpartum rats.

Prostaglandin (PG) D2, a prostanoid known to have hypotensive effect, can evoke increased in vitro prepartum myometrial contraction resulting from up-regulation of the F prostanoid (FP) receptor. The present study further determined postpartum rat uterine responses to PGD2 to evaluate the possibility of the prostanoid becoming a therapeutic for postpartum uterine atony, a major cause of postpartum hemorrhage that can lead to maternal morbidity. In vitro and in vivo postpartum uterine responses to PGD2 were determined and compared to those of prepartum rats. Here we show that in postpartum myometrial strips PGD2 did evoke a contraction sensitive to FP receptor antagonism. Interestingly, this response was not only to a greater extent than that of prepartum rats, but also comparable with the contraction obtained with PGF2α, a therapeutic for postpartum uterine atony but contradicted in conditions including hypertension. Indeed, PGD2 was also found to cause increases of basal uterine contraction under in vivo conditions. Western blots revealed that the expression of FP receptors in postpartum myometrium was higher than that of prepartum rats. Moreover, we noted that the amount of PGD2 produced in postpartum uteri, although lower than that of prepartum rats, was increased compared to non-pregnant conditions. These results thus demonstrate that due to a further up-regulation or high expression of myometrial FP receptors, PGD2 can evoke potent uterine contraction postpartum, and hence the prostanoid, which is naturally synthesized in uterine tissues, could be a potential therapeutic for postpartum uterine atony, especially in settings, such as hypertension.

Formaldehyde induces diabetes-associated cognitive impairments.

Patients with type 2 diabetes mellitus (T2DM) often develop cognitive impairments and have an increased risk of developing Alzheimer's disease. Hyperglycemia is a major characteristic of T2DM, but how elevated glucose levels lead to cognitive decline remains elusive. Here, we report that patients with T2DM and mutations in the formaldehyde (FA)-degrading enzyme aldehyde dehydrogenase 2 ( ALDH2) gene had higher levels of FA and more severe dementia. Injection of FA induced hyperglycemia and cognitive deficits in rats. Ablation of gene expression of ALDH2, the main enzyme to oxidize FA, resulted in abnormally high levels of hippocampal FA, leading to hyperglycemia and cognitive impairments as well as potentiating streptozotocin-induced diabetes development in ALDH2 knockout mice. We found that FA interacts with insulin to form FA-insulin adducts, and these FA-insulin adducts caused insulin deficiency, contributing to memory decline in diabetic rodent models. Reduction of FA by transgenic overexpression of human ALDH2 attenuates hyperglycemia and alleviates cognitive deficits in diabetic mouse models. These findings suggest that excess FA plays a critical role in mediating diabetes-related dementia. Targeting FA and its metabolizing enzyme ALDH2 may be a valid approach for preventing and treating dementia in diabetes mellitus.-Tan, T., Zhang, Y., Luo, W., Lv, J., Han, C., Hamlin, J. N. R., Luo, H., Li, H., Wan, Y., Yang, X., Song, W., Tong, Z. Formaldehyde induces diabetes-associated cognitive impairments.

Renal tubular epithelial cells injury induced by mannitol and its potential mechanism.

Administration of mannitol with high dose could induce extensive isometric renal proximal tubular vacuolization and acute renal failure in clinic. We previously demonstrated that mannitol-induced human kidney tubular epithelial cell (HK-2) injury. The objective of our present work was to further study the cytotoxicity of mannitol in HK-2 cells and its potential mechanism. Cell viability was assessed by an MTT method. Cell morphological changes were observed. Furthermore, levels of malondialdehyde (MDA) and glutathione (GSH) were measured. Flow cytometry was performed to determine cell apoptosis by using Annexin V-FITC and PI. In addition, the F-actin of cells was labeled by FITC-Phalloidin for observation of cytoskeleton. The MTT assay displayed that the cell viability decreased significantly in a dose- and time-dependent manner. The morphological changes were observed, including cell membrane rapture and cell detachment. The GSH concentration in HK-2 cells decreased dramatically in mannitol treatment group, while MDA content increased significantly. The results of flow cytometry indicated that apoptotic percentages of HK-2 cells increased in 250 mmol/L mannitol treatment group. After treatment with 250 mmol/L mannitol for 48 h, HK-2 cells showed disorganization of cytoskeleton and even exhibited a totally destroyed cytoskeleton. Therefore, high dose of mannitol has a toxic effect on renal tubular epithelial cells, which might be attributed to oxidative stress, destroyed cellular cytoskeleton and subsequent cell apoptosis.

Increased role of E prostanoid receptor-3 in prostacyclin-evoked contractile activity of spontaneously hypertensive rat mesenteric resistance arteries.

This study aimed to determine whether E prostanoid receptor-3 (EP3) is involved in prostacyclin (PGI2)-evoked vasoconstrictor activity of resistance arteries and if so, how it changes under hypertensive conditions. Mesenteric resistance arteries from Wistar-Kyoto rats (WKYs) and spontaneously hypertensive rats (SHRs) were isolated for functional and biochemical studies. Here we show that in vessels from WKYs, PGI2 or the endothelial muscarinic agonist ACh (which stimulates in vitro PGI2 synthesis) evoked vasoconstrictor activity, which increased in SHRs. The thromboxane-prostanoid receptor (TP) antagonist SQ29548 partially removed the vasoconstrictor activity, and an increased contractile activity of PGI2 resistant to SQ29548 was observed in SHRs. Interestingly, L798106, an antagonist of EP3 (whose expression was higher in SHRs than in WKYs), not only added to the effect of SQ29548 but also caused relaxation to PGI2 more than that obtained with SQ29548. In accordance, EP3 deletion, which reduced PGI2-evoked contraction, together with SQ29548 resulted in relaxation evoked by the agonist in mouse aortas. These results thus demonstrate an explicit involvement of EP3 in PGI2-evoked vasoconstrictor activity in rat mesenteric resistance arteries and suggest that up-regulation of the receptor contributes significantly to the increased contractile activity evoked by PGI2 under hypertensive conditions.

Prostaglandin D2 is the major cyclooxygenase-1-derived product in prepartum mouse uteri where it mediates an enhanced in vitro myometrial contraction.

This study aimed to determine whether prostaglandin D2 (PGD2) is a major uterine cyclooxygenase (COX) product and if so, we wanted to examine the underlying mechanism, its relation to COX-1-mediated metabolism, and how it influences the in vitro myometrial contraction during the late stage of pregnancy. The production of PGD2 or responses evoked by the prostanoid were determined in uteri isolated from prepartum and/or non-pregnant C57Bl/6 wild-type (WT) or COX-1-/- mice. Results showed that PGD2, which was not detected in non-pregnant counterparts, appears as the major prostanoid in prepartum (<24h prior to parturition) mouse uteri. No signal of PGD2 or other COX-derived products was detected in similar tissues of COX-1-/- mice. Western blot or real-time PCR revealed that expressions of COX-1 and PGD2 synthase (PGDS) in prepartum uteri were higher than those of non-pregnant mice, while both were diminished by the removal of endometrium. Also, we noted that in endometrium-removed prepartum uteri PGD2 evoked an increased contraction compared to that of non-pregnant mice. Antagonizing the F prostanoid (FP) receptor but not D prostanoid receptors abolished the contraction. Moreover, the level of FP receptor mRNAs in endometrium-removed prepartum uteri was increased compared to that of non-pregnant mice. These results imply that due to up-regulations of COX-1 and PGDS in endometrium, PGD2 becomes the major prostanoid produced in prepartum uteri where it can evoke an increased in vitro myometrial contraction, possibly resulting from up-regulation of the FP receptor, the mediator of such a response in mouse uteri.

Role of E-type prostaglandin receptor EP3 in the vasoconstrictor activity evoked by prostacyclin in thromboxane-prostanoid receptor deficient mice.

Prostacyclin, also termed as prostaglandin I2 (PGI2), evokes contraction in vessels with limited expression of the prostacyclin receptor. Although the thromboxane-prostanoid receptor (TP) is proposed to mediate such a response of PGI2, other unknown receptor(s) might also be involved. TP knockout (TP-/-) mice were thus designed and used to test the hypothesis. Vessels, which normally show contraction to PGI2, were isolated for functional and biochemical analyses. Here, we showed that the contractile response evoked by PGI2 was indeed only partially abolished in the abdominal aorta of TP-/- mice. Interestingly, further antagonizing the E-type prostaglandin receptor EP3 removed the remaining contractile activity, resulting in relaxation evoked by PGI2 in such vessels of TP-/- mice. These results suggest that EP3 along with TP contributes to vasoconstrictor responses evoked by PGI2, and hence imply a novel mechanism for endothelial cyclooxygenase metabolites (which consist mainly of PGI2) in regulating vascular functions.

Urine Formaldehyde Predicts Cognitive Impairment in Post-Stroke Dementia and Alzheimer's Disease.

Although Alzheimer's disease (AD) was first described over 100 years ago, there is still no suitable biomarker for diagnosing AD in easily collectable samples (e.g., blood plasma, saliva, and urine). Here, we investigated the relationship between morning urine formaldehyde concentration and cognitive impairment in patients with post-stroke dementia (PSD) or AD in this cross-sectional survey for 7 years. Cognitive abilities of the study participants (n = 577, four groups: 231 controls, 61 stroke, 65 PSD, and 220 AD) were assessed by Mini-Mental State Examination (MMSE). Morning urine formaldehyde concentrations were measured by high performance liquid chromatography (HPLC). Gender- and age-matched participants were selected from the four groups (n = 42 in each group). Both semicarbazide-sensitive amine oxidase (SSAO, a formaldehyde-generating enzyme) and formaldehyde levels in the blood and urine were analyzed by using an enzyme-linked immunosorbent assay (ELISA) and HPLC, respectively. We found that morning urine formaldehyde levels were inversely correlated with MMSE scores. The threshold value (the best Cut-Off value) of formaldehyde concentration for predicting cognitive impairment was 0.0418 mM in patients with PSD (Sensitivity: 92.3%; Specificity: 77.1%), and 0.0449 mM in patients with AD (Sensitivity: 94.1%; Specificity: 81.8%), respectively. The results of biochemical analysis revealed that the observed increase in urine formaldehyde resulted from an overexpression of SSAO in the blood. The findings suggest that measuring the concentration of formaldehyde in overnight fasting urine could be used as a potentially noninvasive method for evaluating the likelihood of ensuing cognitive impairment or dementia.

Angiogenesis inhibitors as therapeutic agents in cancer: Challenges and future directions.

Angiogenesis has become an attractive target for cancer therapy since the US Food and Drug Administration (FDA) approved the first angiogenesis inhibitor (bevacizumab) for the treatment of metastatic colorectal cancer in 2004. In following years, a large number of angiogenesis inhibitors have been discovered and developed, ranging from monoclonal antibodies, endogenous peptides, to small organic molecules and microRNAs. Many of them are now entering the clinical trial, or achieving approval for clinical use. However, major limitations have been observed about angiogenesis inhibitors by continued clinical investigations, such as resistance, enhancing tumor hypoxia and reducing delivery of chemotherapeutic agents, which might be the main reason for poor improvement in overall survival after angiogenesis inhibitor administration in clinic. Therefore, optimal anti-angiogenic therapy strategies become critical. The present review summarizes recent researches in angiogenesis inhibitors, and proposes a perspective on future directions in this field.

Biphasic Effects of Copper on Rat Learning and Memory in the Morris Water Maze.

Dysregulation of copper (Cu) metabolism interrupts neuron function, and subsequently results in neuron degeneration, necrosis, and gliocyte hyperplasia. To further explore the effects of hippocampal Cu concentration on learning and memory, Sprague-Dawley (SD) rats were given once-daily intraperitoneal injections of Copper(II) acetate (Cu(OAc)2) at doses of 0.2, 2, or 20mg/Kg over 5 days. Ultrasonic oscillation dialysis was used to determine the free Cu by graphite furnace atomic absorption spectrometry (GFAAS). Cu administration induced a dose-dependent increase in total hippocampal Cu. However, free hippocampal Cu was found to increase only at the lower concentration of Cu(OAc)2 (0.2 mg/Kg) but decrease at higher concentrations of Cu(OAc)2 (2 and 20 mg/Kg). Higher doses of Cu(OAc)2 (2-20mg/Kg) decreased superoxide dismutase-1 (SOD1) activity, increased both malondialdehyde (MDA) levels and the glutamate/γ-aminobutyric acid (Glu/GABA) ratio, and impaired spatial cognition. However, the lower dose of Cu(OAc)2 (0.2 mg/Kg) showed the opposite effects. This biphasic effect might be attributed to free hippocampal Cu levels and corresponding alterations of Glu/GABA ratio and SOD1 activity.

The endothelial cyclooxygenase pathway: Insights from mouse arteries.

To date, cyclooxygenase-2 (COX-2) is commonly believed to be the major mediator of endothelial prostacyclin (prostaglandin I2; PGI2) synthesis that balances the effect of thromboxane (Tx) A2 synthesis mediated by the other COX isoform, COX-1 in platelets. Accordingly, selective inhibition of COX-2 is considered to cause vasoconstriction, platelet aggregation, and hence increase the incidence of cardiovascular events. This idea has been claimed to be substantiated by experiments on mouse models, some of which are deficient in one of the two COX isoforms. However, results from our studies and those of others using similar mouse models suggest that COX-1 is the major functional isoform in vascular endothelium. Also, although PGI2 is recognized as a potent vasodilator, in some arteries endothelial COX activation causes vasoconstrictor response. This has again been recognized by studies, especially those performed on mouse arteries, to result largely from endothelial PGI2 synthesis. Therefore, evidence that supports a role for COX-1 as the major mediator of PGI2 synthesis in mouse vascular endothelium, reasons for the inconsistency, and results that elucidate underlying mechanisms for divergent vasomotor reactions to endothelial COX activation will be discussed in this review. In addition, we address the possible pathological implications and limitations of findings obtained from studies performed on mouse arteries.