Caffeic acid attenuates neuronal damage, astrogliosis and glial scar formation in mouse brain with cryoinjury

Caffeic acid and diabetic neuropathy: Investigating protective effects and insulin-like growth factor 1 (IGF-1)-related antioxidative and anti-inflammatory mechanisms in mice

Diabetic neuropathy (DN) represents a common and debilitating complication of diabetes, affecting a significant proportion of patients. Despite available treatments focusing on symptom management, there remains an unmet need for therapies that address the underlying pathophysiology. In pursuit of novel interventions, this study evaluated the therapeutic effects of caffeic acid-a natural phenolic compound prevalent in various foods-on diabetic neuropathy using a mouse model, particularly examining its interaction with the Insulin-like Growth Factor 1 (IGF-1) signaling pathway. Caffeic acid was administered orally at two dosages (5 mg/kg and 10 mg/kg), and a comprehensive set of outcomes including fasting blood glucose levels, body weight, sensory behavior, spinal cord oxidative stress markers, inflammatory cytokines, and components of the IGF-1 signaling cascade were assessed. Additionally, to determine the specific contribution of IGF-1 signaling to the observed benefits, IGF1R inhibitor Picropodophyllin (PPP) was co-administered with caffeic acid. Our results demonstrated that caffeic acid, at both dosages, effectively reduced hyperglycemia and alleviated sensory behavioral deficits in diabetic mice. This was accompanied by a marked decrease in oxidative stress markers and an increase in antioxidant enzyme activities within the spinal cord. Significantly lowered microglial activation and inflammatory cytokine expression highlighted the potent antioxidative and anti-inflammatory effects of caffeic acid. Moreover, increases in both serum and spinal levels of IGF-1, along with elevated phosphorylated IGF1R, implicated the IGF-1 signaling pathway as a mediator of caffeic acid's neuroprotective actions. The partial reversal of caffeic acid's benefits by PPP substantiated the pivotal engagement of IGF-1 signaling in mediating its effects. Our findings delineate the capability of caffeic acid to mitigate DN symptoms, particularly through reducing spinal oxidative stress and inflammation, and pinpoint the integral role of IGF-1 signaling in these protective mechanisms. The insights gleaned from this study not only position caffeic acid as a promising dietary adjunct for managing diabetic neuropathy but also highlight the therapeutic potential of targeting spinal IGF-1 signaling as part of a strategic treatment approach.

Caffeic acid recovers ischemia-induced synaptic dysfunction without direct effects on excitatory synaptic transmission and plasticity in mouse hippocampal slices

Caffeic acid is a polyphenolic compound present in a vast array of dietary components. We previously showed that caffeic acid reduces the burden of brain ischemia joining evidence by others that it can attenuate different brain diseases. However, it is unknown if caffeic acid affects information processing in neuronal networks. Thus, we now used electrophysiological recordings in mouse hippocampal slices to test if caffeic acid directly affected synaptic transmission, plasticity and dysfunction caused by oxygen-glucose deprivation (OGD), an in vitro ischemia model. Caffeic acid (1-10 μM) was devoid of effect on synaptic transmission and paired-pulse facilitation in Schaffer collaterals-CA1 pyramidal synapses. Also, the magnitude of either hippocampal long-term potentiation (LTP) or the subsequent depotentiation were not significantly modified by 10 μM caffeic acid. However, caffeic acid (10 μM) increased the recovery of synaptic transmission upon re-oxygenation following 7 minutes of OGD. Furthermore, caffeic acid (10 μM) also recovered plasticity after OGD, as heralded by the increased magnitude of LTP after exposure. These findings show that caffeic acid does not directly affect synaptic transmission and plasticity but can indirectly affect other cellular targets to correct synaptic dysfunction. Unraveling the molecular mechanisms of action of caffeic acid may allow the design of hitherto unrecognized novel neuroprotective strategies.

Non-Enzymatic Antioxidants against Alzheimer's Disease: Prevention, Diagnosis and Therapy

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive memory loss and cognitive decline. Although substantial research has been conducted to elucidate the complex pathophysiology of AD, the therapeutic approach still has limited efficacy in clinical practice. Oxidative stress (OS) has been established as an early driver of several age-related diseases, including neurodegeneration. In AD, increased levels of reactive oxygen species mediate neuronal lipid, protein, and nucleic acid peroxidation, mitochondrial dysfunction, synaptic damage, and inflammation. Thus, the identification of novel antioxidant molecules capable of detecting, preventing, and counteracting AD onset and progression is of the utmost importance. However, although several studies have been published, comprehensive and up-to-date overviews of the principal anti-AD agents harboring antioxidant properties remain scarce. In this narrative review, we summarize the role of vitamins, minerals, flavonoids, non-flavonoids, mitochondria-targeting molecules, organosulfur compounds, and carotenoids as non-enzymatic antioxidants with AD diagnostic, preventative, and therapeutic potential, thereby offering insights into the relationship between OS and neurodegeneration.

Chronic exposure to methadone impairs memory, induces microgliosis, astrogliosis and neuroinflammation in the hippocampus of adult male rats

Methadone is a centrally-acting synthetic opioid analgesic widely used in methadone maintenance therapy (MMT) programs throughout the world. Given its neurotoxic effects, particularly on the hippocampus, this study aims to address the behavioral and histological alterations in the hippocampus associated with methadone administration. To do so, twenty-four adult male albino rats were randomized into two groups, methadone treatment and control. Methadone was administered subcutaneously (2.5-10 mg/kg) once a day for two consecutive weeks. A comparison was drawn with behavioral and structural changes recorded in the control group. The results showed that methadone administration interrupted spatial learning and memory function. Accordingly, treating rats with methadone not only induced cell death but also prompted the actuation of microgliosis, astrogliosis, and apoptotic biomarkers. Furthermore, the results demonstrated that treating rats with methadone decreased the complexity of astrocyte processes and the complexity of microglia processes. These findings suggest that methadone altered the special distribution of neurons. Also, a substantial increase was observed in the expression of TNF-α due to methadone. According to the findings, methadone administration exerts a neurodegenerative effect on the hippocampus via dysregulation of microgliosis, astrogliosis, apoptosis, and neuro-inflammation.

Eco-friendly synthesis of sulphur-doped graphenes with applicability in caffeic acid electrochemical assay

A new electrode based on glassy carbon modified with a sulphur-doped graphene material was successfully developed and applied for caffeic acid (CA) voltammetric detection and quantification. The structural features of sulphur-doped graphene (exfGR-S) characterized by different physicochemical and analytical techniques are presented. Cyclic voltammetry (CV) technique was employed to evaluate the electrochemical behavior of both bare glassy carbon (GCE) and modified GCE/exfGr-S electrodes towards CA oxidation. The study revealed that the modified electrode exhibits superior electrochemical performances compared to the bare electrode, with a broad CA detecting range (from 0.1 to 100.0 µM), a low detection limit 3.03 × 10^-8 M), excellent anti-interference capabilities, as well as good stability and repeatability. The developed electrochemical sensor appears to be a promising candidate for real sample quality control analysis since it successfully displayed its ability to directly detect CA in commercially available coffee product without any pretreatment.

Neuroprotective Effects of Coffee Bioactive Compounds: A Review

Coffee is one of the most widely consumed beverages worldwide. It is usually identified as a stimulant because of a high content of caffeine. However, caffeine is not the only coffee bioactive component. The coffee beverage is in fact a mixture of a number of bioactive compounds such as polyphenols, especially chlorogenic acids (in green beans) and caffeic acid (in roasted coffee beans), alkaloids (caffeine and trigonelline), and the diterpenes (cafestol and kahweol). Extensive research shows that coffee consumption appears to have beneficial effects on human health. Regular coffee intake may protect from many chronic disorders, including cardiovascular disease, type 2 diabetes, obesity, and some types of cancer. Importantly, coffee consumption seems to be also correlated with a decreased risk of developing some neurodegenerative conditions such as Alzheimer's disease, Parkinson's disease, and dementia. Regular coffee intake may also reduce the risk of stroke. The mechanism underlying these effects is, however, still poorly understood. This review summarizes the current knowledge on the neuroprotective potential of the main bioactive coffee components, i.e., caffeine, chlorogenic acid, caffeic acid, trigonelline, kahweol, and cafestol. Data from both in vitro and in vivo preclinical experiments, including their potential therapeutic applications, are reviewed and discussed. Epidemiological studies and clinical reports on this matter are also described. Moreover, potential molecular mechanism(s) by which coffee bioactive components may provide neuroprotection are reviewed.

Neurobiological effects of phospholipids in vitro: Relevance to stress-related disorders

Nutrition is a crucial component for maintenance of brain function and mental health. Accumulating evidence suggests that certain molecular compounds derived from diet can exert neuroprotective effects against chronic stress, and moreover improve important neuronal processes vulnerable to the stress response, such as plasticity and neurogenesis. Phospholipids are naturally occurring amphipathic molecules with promising potential to promote brain health. However, it is unclear whether phospholipids are able to modulate neuronal function directly under a stress-related context. In this study, we investigate the neuroprotective effects of phosphatidylcholine (PC), lysophosphatidylcholine (LPC), phosphatidylserine (PS), phosphatidylethanolamine (PE), phosphatidylinositol (PI), phosphatidylglycerol (PG), phosphatidic acid (PA), sphingomyelin (SM) and cardiolipin (CL) against corticosterone (CORT)-induced cytotoxicity in primary cultured rat cortical neurons. In addition, we examine their capacity to modulate proliferation and differentiation of hippocampal neural progenitor cells (NPCs).

We show that PS, PG and PE can reverse CORT-induced cytotoxicity and neuronal depletion in cortical cells. On the other hand, phospholipid exposure was unable to prevent the decrease of Bdnf expression produced by CORT. Interestingly, PS was able to increase hippocampal NPCs neurosphere size, and PE elicited a significant increase in astrocytic differentiation in hippocampal NPCs. Together, these results indicate that specific phospholipids protect cortical cells against CORT-induced cytotoxicity and improve proliferation and astrocytic differentiation in hippocampal NPCs, suggesting potential implications on neurodevelopmental and neuroprotective pathways relevant for stress-related disorders.

Identification of Caffeic Acid Phenethyl Ester (CAPE) as a Potent Neurodifferentiating Natural Compound That Improves Cognitive and Physiological Functions in Animal Models of Neurodegenerative Diseases

Cell-based screening of bioactive compounds has served as an important gateway in drug discovery. In the present report, using human neuroblastoma cells and enrolling an extensive three-step screening of 57 phytochemicals, we have identified caffeic acid phenethyl ester (CAPE) as a potent neurodifferentiating natural compound. Analyses of control and CAPE-induced neurodifferentiated cells revealed: (i) modulation of several key proteins (NF200, MAP-2, NeuN, PSD95, Tuj1, GAP43, and GFAP) involved in neurodifferentiation process; and (ii) attenuation of neuronal stemness (HOXD13, WNT3, and Msh-2) and proliferation-promoting (CDC-20, CDK-7, and BubR1) proteins. We anticipated that the neurodifferentiation potential of CAPE may be beneficial for the treatment of neurodegenerative diseases and tested it using the Drosophila model of Alzheimer’s disease (AD) and mice model of amnesia/loss of memory. In both models, CAPE exhibited improved disease symptoms and activation of physiological functions. Remarkably, CAPE-treated mice showed increased levels of neurotrophin-BDNF, neural progenitor marker-Nestin, and differentiation marker-NeuN, both in the cerebral cortex and hippocampus. Taken together, we demonstrate the differentiation-inducing and therapeutic potential of CAPE for neurodegenerative diseases.

Naturally Derived Polyphenols Protect Against Corticosterone-Induced Changes in Primary Cortical Neurons

BACKGROUND

Polyphenols are phytochemicals that have been associated with therapeutic effects in stress-related disorders. Indeed, studies suggest that polyphenols exert significant neuroprotection against multiple neuronal injuries, including oxidative stress and neuroinflammation, but the mechanisms are unclear. Evidence indicates that polyphenol neuroprotection may be mediated by activation of Nrf2, a transcription factor associated with antioxidant and cell survival responses. On the other hand, in stress-linked disorders, Fkbp5 is a novel molecular target for treatment because of its capacity to regulate glucocorticoid receptor sensitivity. However, it is not clear the role Fkbp5 plays in polyphenol-mediated stress modulation. In this study, the neuroprotective effects and mechanisms of the naturally derived polyphenols xanthohumol and quercetin against cytotoxicity induced by corticosterone were investigated in primary cortical cells.

METHODS

Primary cortical cells containing both neurons and astrocytes were pre-incubated with different concentrations of quercetin and xanthohumol to examine the neuroprotective effects of polyphenols on cell viability, morphology, and gene expression following corticosterone insult.

RESULTS

Both polyphenols tested prevented the reduction of cell viability and alterations of neuronal/astrocytic numbers due to corticosterone exposure. Basal levels of Bdnf mRNA were also decreased after corticosterone insult; however, this was reversed by both polyphenol treatments. Interestingly, the Nrf2 inhibitor blocked xanthohumol but not quercetin-mediated neuroprotection. In contrast, we found that Fkbp5 expression is exclusively modulated by quercetin.

CONCLUSIONS

These results suggest that naturally derived polyphenols protect cortical cells against corticosterone-induced cytotoxicity and enhance cell survival via modulation of the Nrf2 pathway and expression of Fkbp5.

Health promoting properties of blueberries: a review

With the strengthening of the link between diet and health, several foodstuffs have emerged as possessing potential health benefits such as phenolic rich fruits and vegetables. Blueberries, along with other berries, given their flavonoid and antioxidant content have long since been considered as a particularly interesting health promoting fruit. Therefore, the present work aimed to compile the existing evidences regarding the various potential benefits of blueberry and blueberry based products consumption, giving particular relevance to in vivo works and epidemiological studies whenever available. Overall, the results demonstrate that, while the evidences that support a beneficial role of blueberry and blueberry extracts consumption, further human based studies are still needed.

Huangqin flavonoid extraction for spinal cord injury in a rat model

Flavonoids from Huangqin (dried roots of Scutellaria baicalensis Georgi) have anti-inflammatory effects, and are considered useful for treatment of spinal cord injury. To verify this hypothesis, the T9–10 spinal cord segments of rats were damaged using Allen's method to establish a rat spinal cord injury model. Before model establishment, Huangqin flavonoid extraction (12.5 g/kg) was administered intragastrically for 1 week until 28 days after model establishment. Methylprednisolone (30 mg/kg) was injected into the tail vein at 30 minutes after model establishment as a positive control. Basso, Beattie, and Bresnahan locomotor scale scores were used to assess hind limb motor function. Hematoxylin-eosin staining was used to detect pathological changes in the injured spinal cord. Immunofluorescence and western blot assays were performed to measure immunoreactivity and expression levels of brain-derived neurotrophic factor, neuronal marker neurofilament protein, microglial marker CD11b and astrocyte marker glial fibrillary acidic protein in the injured spinal cord. Huangqin flavonoid extraction markedly reduced spinal cord hematoma, inflammatory cell infiltration and cavities and scars, and increased the Basso, Beattie, and Bresnahan locomotor scale scores; these effects were identical to those of methylprednisolone. Huangqin flavonoid extraction also increased immunoreactivity and expression levels of brain-derived neurotrophic factor and neurofilament protein, and reduced immunoreactivity and expression levels of CD11b and glial fibrillary acidic protein, in the injured spinal cord. Overall, these data suggest that Huangqin flavonoid extraction can promote recovery of spinal cord injury by inducing brain-derived neurotrophic factor and neurofilament protein expression, reducing microglia activation and regulating reactive astrocytes.

Synthesis and Functional Characterization of Caffeic Acid Glucoside Using Leuconostoc mesenteroides Dextransucrase

Caffeic acid was modified via transglucosylation using sucrose and dextransucrase from Leuconostoc mesenteroides B-512FMCM. Following enzymatic modification, a caffeic acid glucoside was isolated by butanol separation, silica gel chromatography, and preparative HPLC. The synthesized caffeic acid glucoside had a molecular mass-to-charge ratio of 365 m/z, and its structure was identified as caffeic acid-3-O-α-d-glucopyranoside. The production of this caffeic acid-3-O-α-d-glucopyranoside at a concentration of 153 mM was optimized using 325 mM caffeic acid, 355 mM sucrose, and 650 mU mL^-1 dextransucrase in the synthesis reaction. In comparison with the caffeic acid, the caffeic acid-3-O-α-d-glucopyranoside displayed 3-fold higher water solubility, 1.66-fold higher antilipid peroxidation effect, 15% stronger inhibition of colon cancer cell growth, and 11.5-fold higher browning resistance. These results indicate that this caffeic acid-3-O-α-d-glucopyranoside may be a suitable functional component of food and pharmaceutical products.

In Vitro Study on Glucose Utilization Capacity of Bioactive Fractions of Houttuynia cordata in Isolated Rat Hemidiaphragm and Its Major Phytoconstituent

Objective. The whole plant of Houttuynia cordata has been reported to have potent antihyperglycemic activity. Therefore, the present study was undertaken to investigate the glucose utilization capacity of bioactive fractions of ethanol extract of Houttuynia cordata (HC) in isolated rat hemidiaphragm. Methods. All the fractions, that is, aqueous (AQ), hexane (HEX), chloroform (CHL), and ethyl acetate (EA), obtained from ethanol extract of H. cordata were subjected to phytochemical standardization use in quercetin as a marker with the help of HPTLC. Further, glucose utilization capacity by rat hemidiaphragm was evaluated in 12 different sets of in vitro experiments. In the study, different fractions from H. cordata as mentioned above were evaluated, where insulin was used as standard and quercetin as a biological standard. Results. Among all the tested fractions, AQ and EA significantly increased glucose uptake by isolated rat hemidiaphragm compared to negative control. Moreover, AQ fractions enhanced the uptake of glucose significantly (p < 0.05) and was found to be more effective than insulin. Conclusions. The augmentation in glucose uptake by hemidiaphragm in presence of AQ and EA fractions may be attributed to the presence of quercetin, which was found to be 7.1 and 3.2% w/w, respectively, in both the fractions.

The protective effect of caffeic acid on global cerebral ischemia-reperfusion injury in rats

Ischemic stroke is a major cause of death and disability all over the world. Ischemic stroke results from a temporary or permanent reduction of cerebral blood flow that leads to functional and structural damage in different brain regions. Despite decades of intense research, the beneficial treatment of stroke remains limited. In light of this, the search for effective means ameliorating cerebral ischemia-reperfusion injury (CIRI) is one of the major problems of experimental medicine and biology. Recently, the 5-Lipoxygenase (5-LO, a key enzyme metabolizing arachidonic acid to produce leukotrienes) inhibitors have been showed to protect brain against ischemic damage in animal model of cerebral ischemia. Caffeic acid, an inhibitor of 5-LO, is a phenolic compound widely distributed in medicinal plants. The aim of this study was to investigate the effect of caffeic acid on global cerebral ischemia-reperfusion injury in rats. The study was carried out on 45 rats that were randomly divided into five groups: the sham group (n = 9), I/R non-treated group (n = 9), I/R-caffeic acid group (10 mg · kg⁻¹) (n = 9), I/R-caffeic acid group (30 mg · kg⁻¹) (n = 9) and I/R-caffeic acid group (50 mg · kg⁻¹) (n = 9). Global cerebral ischemia was induced by bilateral carotid artery occlusion for 20 min followed by reperfusion. Spatial learning and memory was evaluated using Morris water maze. Histopathological changes of hippocampus neurons was observed using HE staining. Superoxide dismutase (SOD, the antioxidant enzyme) activities and malondialdehyde (MDA, an oxidative stress biomarker) contents were detected. NF-κBp65 expression was detected by the methods of immunohistochemistry. Caffeic acid markedly reduced the escape latency, relieved hippocampal neurons injury and increased neuron count compared with those of I/R non-treated rat. NF-κBp65 expression and MDA content decreased significantly, and SOD activities increased significantly in hippocampus. Compared with sham group, 5-LO expression increase significantly in I/R non-treated group rat, and caffeic acid markedly reduced 5-LO expression. The results of the study suggest that caffeic acid has a significant protective effect on global cerebral ischemia-reperfusion injury in rats. The neuroprotective effects is likely to be mediated through the inhibition of 5-LO.

Phenolic profiling in the pulp and peel of nine plantain cultivars (Musa sp.)

The present study investigated the phenolic profiles of the pulp and peel of nine plantain cultivars and compared them to those of two dessert bananas of commercial interest (Grand Nain and Gros Michel), alongside a newly created hybrid, resistant to black sigatoka disease (F568). Identification and quantification of phenolic compounds were performed by means of HPLC-ESI-HR-MS and HPLC-DAD. Hydroxycinnamic acids, particularly ferulic acid-hexoside with 4.4-85.1 μg/g of dry weight, dominated in the plantain pulp and showed a large diversity among cultivars. Flavonol glycosides were predominant in plantain peels, rutin (242.2-618.7 μg/g of dry weight) being the most abundant. A principal component analysis on the whole data revealed that the phenolic profiles of the hybrid, the dessert bananas and the pure plantains differed from each other. Plantain pulps and peels appeared as good sources of phenolics, which could be involved in the health benefits associated with their current applications.

Houttuynia cordata Improves Cognitive Deficits in Cholinergic Dysfunction Alzheimer's Disease-Like Models

Cognitive impairment is a result of dementia of diverse causes, such as cholinergic dysfunction and Alzheimer's disease (AD). Houttuynia cordata Thunb. (Saururaceae) has long been used as a traditional herbal medicine. It has biological activities including protective effects against amyloid beta (Aβ) toxicity, via regulation of calcium homeostasis, in rat hippocampal cells. To extend previous reports, we investigated the effects of water extracts of H. cordata herb (HCW) on tauopathies, also involving calcium influx. We then confirmed the effects of HCW in improving memory impairment and neuronal damage in mice with Aβ-induced neurotoxicity. We also investigated the effects of HCW against scopolamine-induced cholinergic dysfunction in mice. In primary neuronal cells, HCW inhibited the phosphorylation of tau by regulating p25/p35 expression in Aβ-induced neurotoxicity. In mice with Aβ-induced neurotoxicity, HCW improved cognitive impairment, as assessed with behavioral tasks, such as novel object recognition, Y-maze, and passive avoidance tasks. HCW also inhibited the degeneration of neurons in the CA3 region of the hippocampus in Aβ-induced neurotoxicity. Moreover, HCW, which had an IC50 value of 79.7 μg/ml for acetylcholinesterase inhibition, ameliorated scopolamine-induced cognitive impairment significantly in Y-maze and passive avoidance tasks. These results indicate that HCW improved cognitive impairment, due to cholinergic dysfunction, with inhibitory effects against tauopathies and cholinergic antagonists, suggesting that HCW may be an interesting candidate to investigate for the treatment of AD.

Preparation of MIP-based QCM nanosensor for detection of caffeic acid

In the present work, a new caffeic acid imprinted quartz crystal microbalance (QCM) nanosensor has been designed for selective assignation of caffeic acid in plant materials. Methacrylamidoantipyrine-iron(III) [MAAP-Fe(III)] as metal-chelating monomer has been used to prepare selective molecular imprinted polymer (MIP). MIP film for detection of caffeic acid has been developed on QCM electrode and selectivity experiments and analytical performance of caffeic acid imprinted QCM nanosensor has been studied. The caffeic acid imprinted QCM nanosensor has been characterized by AFM. After the characterization studies, imprinted and non-imprinted nanosensors was connected to QCM system for studies of connection of the target molecule, selectivity and the detection of amount of target molecule in real samples. The detection limit was found to be 7.8 nM. The value of Langmuir constant (b) (4.06 × 10(6)) that was acquired using Langmuir graph demonstrated that the affinity of binding sites was strong. Also, selectivity of prepared caffeic acid imprinted nanosensor was found as being high compared to chlorogenic acid. Finally, the caffeic acid levels in plant materials was determined by the prepared QCM nanosensor.

Reciprocal modulation between microglia and astrocyte in reactive gliosis following the CNS injury

Reactive gliosis, also known as glial scar formation, is an inflammatory response characterized by the proliferation of microglia and astrocytes as well as astrocytic hypertrophy following injury in the central nervous system (CNS). The glial scar forms a physical and molecular barrier to isolate the injured area from adjacent normal nervous tissue for re-establishing the integrity of the CNS. It prevents the further spread of cellular damage but represents an obstacle to regrowing axons. In this review, we integrated the current findings to elucidate the tightly reciprocal modulation between activated microglia and astrocytes in reactive gliosis and proposed that modification of cellular response to the injury or cellular reprogramming in the glial scar could lead advances in axon regeneration and functional recovery after the CNS injury.

Neuroprotective effect of Pycnogenol® following traumatic brain injury

Traumatic brain injury (TBI) involves primary and secondary injury cascades that underlie delayed neuronal dysfunction and death. Oxidative stress is one of the most celebrated secondary injury mechanisms. A close relationship exists between levels of oxidative stress and the pathogenesis of TBI. However, other cascades, such as an increase in proinflammatory cytokines, also play important roles in the overall response to the trauma. Pharmacologic intervention, in order to be successful, requires a multifaceted approach. Naturally occurring flavonoids are unique in possessing not only tremendous free radical scavenging properties but also the ability to modulate cellular homeostasis leading to a reduction in inflammation and cell toxicity. This study evaluated the therapeutic role of Pycnogenol (PYC), a patented combinational bioflavonoid. Young adult Sprague-Dawley rats were subjected to a unilateral moderate cortical contusion and treated post injury with PYC or vehicle. At either 48 or 96 h post trauma, the animals were killed and the cortex and hippocampus analyzed for changes in enzymatic and non-enzymatic oxidative stress markers. In addition, possible changes in both pre- and post-synaptic proteins (synapsin-1, PSD-95, drebrin, synapse associated protein-97) were analyzed. Finally, a separate cohort of animals was used to evaluate two proinflammatory cytokines (IL-6, TNF-α). Following the trauma there was a significant increase in oxidative stress in both the injured cortex and the ipsilateral hippocampus. Animals treated with PYC significantly ameliorated levels of protein carbonyls, lipid peroxidation, and protein nitration. The PYC treatment also significantly reduced the loss of key pre- and post-synaptic proteins with some levels in the hippocampus of PYC treated animals not significantly different from sham operated controls. Although levels of the proinflammatory cytokines were significantly elevated in both injury groups, the cohort treated with PYC showed a significant reduction compared to vehicle treated controls. These results are the first to show a neuroprotective effect of PYC following TBI. They also suggest that the diverse effects of bioflavonoids may provide a unique avenue for possible therapeutic intervention following head trauma.

Transforming growth factor β1-induced astrocyte migration is mediated in part by activating 5-lipoxygenase and cysteinyl leukotriene receptor 1

BACKGROUND

Transforming growth factor-β 1 (TGF-β 1) is an important regulator of cell migration and plays a role in the scarring response in injured brain. It is also reported that 5-lipoxygenase (5-LOX) and its products, cysteinyl leukotrienes (CysLTs, namely LTC₄, LTD₄ and LTE₄), as well as cysteinyl leukotriene receptor 1 (CysLT₁R) are closely associated with astrocyte proliferation and glial scar formation after brain injury. However, how these molecules act on astrocyte migration, an initial step of the scarring response, is unknown. To clarify this, we determined the roles of 5-LOX and CysLT₁R in TGF-β 1-induced astrocyte migration.

METHODS

In primary cultures of rat astrocytes, the effects of TGF-β 1 and CysLT receptor agonists on migration and proliferation were assayed, and the expression of 5-LOX, CysLT receptors and TGF-β1 was detected. 5-LOX activation was analyzed by measuring its products (CysLTs) and applying its inhibitor. The role of CysLT₁R was investigated by applying CysLT receptor antagonists and CysLT₁R knockdown by small interfering RNA (siRNA). TGF-β 1 release was assayed as well.

RESULTS

TGF-β 1-induced astrocyte migration was potentiated by LTD₄, but attenuated by the 5-LOX inhibitor zileuton and the CysLT₁R antagonist montelukast. The non-selective agonist LTD₄ at 0.1 to 10 nM also induced a mild migration; however, the selective agonist N-methyl-LTC₄ and the selective antagonist Bay cysLT2 for CysLT₂R had no effects. Moreover, CysLT₁R siRNA inhibited TGF-β 1- and LTD₄-induced astrocyte migration by down-regulating the expression of this receptor. However, TGF-β 1 and LTD4 at various concentrations did not affect astrocyte proliferation 24 h after exposure. On the other hand, TGF-β 1 increased 5-LOX expression and the production of CysLTs, and up-regulated CysLT1R (not CysLT₂R), while LTD4 and N-methyl-LTC4 did not affect TGF-β 1 expression and release.

CONCLUSIONS

TGF-β 1-induced astrocyte migration is, at least in part, mediated by enhanced endogenous CysLTs through activating CysLT₁R. These findings indicate that the interaction between the cytokine TGF-β 1 and the pro-inflammatory mediators CysLTs in the regulation of astrocyte function is relevant to glial scar formation.

Aquaporin-4 deficiency attenuates acute lesions but aggravates delayed lesions and microgliosis after cryoinjury to mouse brain

OBJECTIVE

To determine whether aquaporin-4 (AQP4) regulates acute lesions, delayed lesions, and the associated microglial activation after cryoinjury to the brain.

METHODS

Brain cryoinjury was applied to AQP4 knockout (KO) and wild-type mice. At 24 h and on days 7 and 14 after cryoinjury, lesion volume, neuronal loss, and densities of microglia and astrocytes were determined, and their changes were compared between AQP4 KO and wild-type mice.

RESULTS

Lesion volume and neuronal loss in AQP4 KO mice were milder at 24 h following cryoinjury, but worsened on days 7 and 14, compared to those in wild-type mice. Besides, microglial density increased more, and astrocyte proliferation and glial scar formation were attenuated on days 7 and 14 in AQP4 KO mice.

CONCLUSION

AQP4 deficiency ameliorates acute lesions, but worsens delayed lesions, perhaps due to the microgliosis in the late phase.

Caffeic Acid phenethyl ester protects blood-brain barrier integrity and reduces contusion volume in rodent models of traumatic brain injury

A number of studies have established a deleterious role for inflammatory molecules and reactive oxygen species (ROS) in the pathology of traumatic brain injury (TBI). Caffeic acid phenethyl ester (CAPE) has been shown to exert both antioxidant and anti-inflammatory effects. The primary objective of the present study was to examine if CAPE could be used to reduce some of the pathological consequences of TBI using rodent models. Male Sprague-Dawley rats and C57BL/6 mice were subjected to controlled cortical impact (CCI) injury. Blood-brain barrier (BBB) integrity was assessed by examining claudin-5 expression and the extravasation of Evans blue dye. The effect of post-injury CAPE administration on neurobehavioral function was assessed using vestibulomotor, motor, and two hippocampus-dependent learning and memory tasks. We report that post-TBI administration of CAPE reduces Evans blue extravasation both in rats and mice. This improvement was associated with preservation of the levels of the tight junction protein claudin-5. CAPE treatment did not improve performance in either vestibulomotor/motor function (tested using beam balance and foot-fault tests), or in learning and memory function (tested using the Morris water maze and associative fear memory tasks). However, animals treated with CAPE were found to have significantly less cortical tissue loss than vehicle-treated controls. These findings suggest that CAPE may provide benefit in the treatment of vascular compromise following central nervous system injury.

Houttuyniae Herba protects rat primary cortical cells from Aβ(25-35)-induced neurotoxicity via regulation of calcium influx and mitochondria-mediated apoptosis

Amyloid beta (Aβ) fibrils are believed to play a major role in the pathogenesis of Alzheimer's disease. Although the mechanisms underlying Aβ toxicity remain largely unknown, Aβ fibrils disrupt calcium homeostasis and generate free radicals, resulting in oxidative stress, mitochondrial dysfunction, and apoptotic cell death. Houttuyniae Herba, the aerial part of Houttuynia cordata Thunb. (Saururaceae), is a commonly used herb in traditional Asian medicine. It has been reported to have various bioactivities, including antioxidant effects. In the present study, we investigated the protective effect of standardised Houttuyniae Herba water extract (HCW) against Aβ(25-35)-induced neurotoxicity and its possible mechanisms in rat primary cortical cells. Pretreatment with HCW attenuated the cell damage caused by 8 μM Aβ(25-35) exposure, as evidenced by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, a lactate dehydrogenase assay, and microtubule-associated protein 2 immunostaining. Moreover, HCW inhibited the Aβ(25-35)-induced elevation of the intracellular calcium level, reactive oxygen species overproduction, mitochondrial membrane potential disruption, and caspase 3 activation. These results indicate that HCW protects rat primary cortical neurons against Aβ(25-35)-induced toxicity via the regulation of calcium and the inhibition of mitochondria-mediated apoptosis.

Antioxidant, antinociceptive, and anti-inflammatory activities of Xanthii Fructus extract

ETHNOPHARMACOLOGICAL RELEVANCE

Xanthii seeds commonly called Cang-Erzi were used as a traditional Chinese medicine for treating sinusitis, headache due to rheumatism and skin pruritus.

AIM OF THE STUDY

In order to evaluate the actions of this plant, studies were performed on antioxidant, antinociceptive, and anti-inflammatory activities.

MATERIALS AND METHODS

The aqueous extract of Xanthii Fructus (AXF) was evaluated in mice for anti-inflammatory activity using carrageenan-induced hind paw edema model. The antinociceptive activity of AXF was evaluated by writhing and formalin tests. Antioxidant properties were assayed in terms of antioxidant activity by scavenging abilities on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS), reducing activity and liposome protection. In addition, the total phenolic content was determined with spectrophotometric method.

RESULTS

AXF exhibited significant radical scavenging and reducing activity. And oral treatment with AXF elicited inhibitory activity on acetic acid effect and reduced the formalin effect at the late-phase. In the anti-inflammatory test, AXF inhibited the development of paw edema induced by λ-carrageenan (Carr). AXF decreased the paw edema at the fifth hour after Carr administration, and increased the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in the liver tissue and decreased the malondialdehyde (MDA) level in the edema paw. AXF decreased the level of serum nitric oxide (NO) and tumor necrosis factor (TNF)-α after Carr injection and AXF decreased the levels of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions in paw edema at the fifth hour.

CONCLUSIONS

AXF shows antioxidant, antinociceptive, and anti-inflammatory activities, supporting the folkloric usage of the plant to treat various inflammatory diseases.

Rapid screening and identification of caffeic acid and its esters in Erigeron breviscapus by ultra-performance liquid chromatography/tandem mass spectrometry

Caffeic acid and its esters (CAEs) are widely distributed in the plant kingdom and have been reported to elicit a wide range of exceptional biological activities. Present methods for screening and characterization of CAEs normally need the use of liquid chromatography diode-array detection/multistage mass spectrometry (LC-DAD/MS(n)). In this report, a rapid and efficient method coupling ultra-performance liquid chromatography (UPLC) with fragment-targeted multi-reaction monitoring (MRM) has been developed for screening CAEs in a crude extract of Erigeron breviscapus, while a UPLC/quasi-MS(n) method has been applied in the structural identification of these compounds. Furthermore, a simple quasi-UPLC/MS/MS method based on in-source collision-induced dissociation (CID) has been proposed for rapid identification of the CAEs. As a result, a total of more than 34 CAEs were detected and their structures characterized. Nine of them were reported from E. breviscapus for the first time. Applications of these strategies in the chemical investigation of an injection of E. breviscapus resulted in the identifications of 16 CAEs. These strategies, if appropriate modifications are made, will be very useful in screening and characterization not only of CAEs, but of other structural types of compounds in various complex matrices.

Astrogliosis in CNS pathologies: is there a role for microglia?

Astrogliosis, a cellular reaction with specific structural and functional characteristics, represents a remarkably homotypic response of astrocytes to all kinds of central nervous system (CNS) pathologies. Astrocytes play diverse functions in the brain, both harmful and beneficial. Mounting evidence indicates that astrogliosis is an underlying component of a diverse range of diseases and associated neuropathologies. The mechanisms that lead to astrogliosis are not fully understood, nevertheless, damaged neurons have long been reported to induce astrogliosis and astrogliosis has been used as an index for underlying neuronal damage. As the predominant source of proinflammatory factors in the CNS, microglia are readily activated under certain pathological conditions. An increasing body of evidence suggests that release of cytokines and other soluble products by activated microglia can significantly influence the subsequent development of astrogliosis and scar formation in CNS. It is well known that damaged neurons activate microglia very quickly, therefore, it is possible that activated microglia contribute factors/mediators through which damaged neuron induce astrogliosis. The hypothesis that activated microglia initiate and maintain astrogliosis suggests that suppression of microglial overactivation might effectively attenuate reactive astrogliosis. Development of targeted anti-microglial activation therapies might slow or halt the progression of astrogliosis and, therefore, help achieve a more beneficial environment in various CNS pathologies.

Experimental cryosurgery investigations in vivo

Cryosurgery is the use of freezing temperatures to elicit an ablative response in a targeted tissue. This review provides a global overview of experimentation in vivo which has been the basis of advancement of this widely applied therapeutic option. The cellular and tissue-related events that underlie the mechanisms of destruction, including direct cell injury (cryolysis), vascular stasis, apoptosis and necrosis, are described and are related to the optimal methods of technique of freezing to achieve efficacious therapy. In vivo experiments with major organs, including wound healing, the putative immunological response following thawing, and the use of cryoadjunctive strategies to enhance cancer cell sensitivity to freezing, are described.