Synaptamide Ameliorates Hippocampal Neurodegeneration and Glial Activation in Mice with Traumatic Brain Injury.

Traumatic brain injury (TBI) is a major concern for public health worldwide, affecting 55 million people and being the leading cause of death and disability. To improve the outcomes and effectiveness of treatment for these patients, we conducted a study on the potential therapeutic use of N-docosahexaenoylethanolamine (synaptamide) in mice using the weight-drop injury (WDI) TBI model. Our study focused on exploring synaptamide's effects on neurodegeneration processes and changes in neuronal and glial plasticity. Our findings showed that synaptamide could prevent TBI-associated working memory decline and neurodegenerative changes in the hippocampus, and it could alleviate decreased adult hippocampal neurogenesis. Furthermore, synaptamide regulated the production of astro- and microglial markers during TBI, promoting the anti-inflammatory transformation of the microglial phenotype. Additional effects of synaptamide in TBI include stimulating antioxidant and antiapoptotic defense, leading to the downregulation of the Bad pro-apoptotic marker. Our data suggest that synaptamide has promising potential as a therapeutic agent to prevent the long-term neurodegenerative consequences of TBI and improve the quality of life.

Anti-Inflammatory Activity of Synaptamide in the Peripheral Nervous System in a Model of Sciatic Nerve Injury.

N-docosahexaenoylethanolamine (DHEA), or synaptamide, is an endogenous metabolite of docosahexaenoic acid (DHA) that exhibits synaptogenic and neurogenic effects. In our previous studies, synaptamide administration inhibited the neuropathic pain-like behavior and reduced inflammation in the central nervous system following sciatic nerve injury. In the present study, we examine the effect of synaptamide on the peripheral nervous system in a neuropathic pain condition. The dynamics of ionized calcium-binding adapter molecule 1 (iba-1), CD68, CD163, myelin basic protein, and the production of interleukin 1ß and 6 within the sciatic nerve, as well as the neuro-glial index and the activity of iba-1, CD163, glial fibrillary acidic protein (GFAP), neuronal NO synthase (nNOS), substance P (SP), activating transcription factor 3 (ATF3) in the dorsal root ganglia (DRG), are studied. According to our results, synaptamide treatment (4 mg/kg/day) (1) decreases the weight-bearing deficit after nerve trauma; (2) enhances the remyelination process in the sciatic nerve; (3) shows anti-inflammatory properties in the peripheral nervous system; (4) decreases the neuro-glial index and GFAP immunoreactivity in the DRG; (5) inhibits nNOS- and SP-ergic activity in the DRG, which might contribute to neuropathic pain attenuation. In general, the current study demonstrates the complex effect of synaptamide on nerve injury, which indicates its high potential for neuropathic pain management.

Analgesic Activity of Synaptamide in a Rat Sciatic Nerve Chronic Constriction Injury Model.

At present, there is a growing interest in the study of the neurotropic activity of polyunsaturated fatty acid ethanolamides (N-acylethanolamines). N-docosahexaenoylethanolamine (DHEA), or synaptamide, an endogenous metabolite of docosahexaenoic acid, is a promising compound with anti-inflammatory activity. The results of this study demonstrate that synaptamide, when administered subcutaneously (4 mg/kg/day, 35 days), promotes a decrease in cold allodynia and mechanical hyperalgesia in a rat sciatic nerve chronic constriction injury (CCI) model. After CCI, synaptamide treatment enhanced the remyelination process in the site of sciatic nerve injury (33.4 ± 1.1% in the CCI+Syn group, compared to 28.4 ± 0.9% in the CCI group). Further, synaptamide suppressed the CCI-induced increase in the activity of microglia (13.1 ± 0.5% in CCI+Syn, compared to 15.3 ± 0.7% in the CCI group) and the number of nitric oxide synthase-positive neurons (58,307 ± 5,206 cells/mm3 in CCI+Syn, compared to 80,288 ± 4,287 cells/mm3 in the CCI group) in the dorsal horns of the spinal cord, and also reduced the concentration of interleukin 1 beta in the spinal cord (169.3 ± 4 pg/mg of protein in CCI+Syn, compared to 236.9 ± 9.3 pg/mg of protein in CCI group) 35 days after surgery. Synaptamide treatment resulted in decrease of reactive astrogliosis in the spinal cord dorsal horns to 20.8 ± 1.3%, which occurred simultaneously with a decrease in the substance P (SP) level (9.8 ± 0.5%) compared to vehicle-treated animals (30.2 ± 2.2% and 13.4 ± 0.9% of astroglia and SP staining area, respectively). In addition, synaptamide increased superoxide dismutase activity up to 68.6 ± 0.8% (control 50.6 ± 0.9%) in astrocyte culture. Thus, synaptamide provides anti-inflammatory and neuroprotective effects in both peripheral and central nervous system after sciatic nerve injury.

Chimyl Alcohol Exhibits Proinflammatory Activity in vivo and in vitro.

Marine organisms are among the prominent and abundant sources of 1-O-alkyl-sn-glycerols, including chimyl alcohol (CA), batyl alcohol and selachyl alcohol. These biologically active compounds are precursors in plasmalogen and phospholipid biosynthesis, which are the main irreplaceable components of cell membranes. The results of this study demonstrate that CA promotes the activation of immune processes in the mouse spleen and in the mouse macrophage cell culture RAW 264.7. We studied the effect of CA on the spleen weight, as well as on the proliferation process and expression of interleukin-1ß (IL-1ß) and CD86 - a marker of the proinflammatory M1-type macrophage cell surface in experimental animals. We used the RAW 264.7 macrophage cell culture to assess the CA cytotoxicity, its effect on reactive oxygen species (ROS), nitric oxide (NO) production and lysosomal activity, as well as IL-1ß and CD86 expression in vitro. In vivoand in vitro experiments have shown that CA: (1) enhances cell proliferation without changing the spleen's weight, (2) increases the activity of the proinflammatory marker CD86, (3) increases the level of ROS/NO/lysosome activity, and (4) does not affect the level of IL-1ß. Our study reveals that CA has a complex immunostimulation effect in vitro and in vivo, which opens up prospects for further study of its biological activity.

Mild Traumatic Brain Injury Contributes to the Development of Delayed Neuroinflammation.

INTRODUCTION: In recent years, according to the literature, the problem of mild traumatic brain injury (mTBI) has become more and more urgent. Compared to moderate to severe craniocerebral trauma, mTBI occurs in a far greater number of people. The delayed sequelae caused by a single mTBI or multiple mTBIs are a significant public health problem. METHODS: A weight-drop model was used for the formation of mTBI. A metal rod weighing 337 g with a blunt tip of 3 mm diameter was uplifted at 8 cm height and held by a lever. The trauma was created by lowering the lever and the rod and free-dropping onto the rat skull. In the cerebral cortex of experimental animals, we analyzed the level of microglial activity (Iba-1-positive system) and the expression of pro-inflammatory markers (IL1ß, IL6, and CD86). Also, the expression level of the endocannabinoid system receptor (cannabinoid receptor type 1 [CB1]) was assessed in brain samples. RESULTS: Experiments have shown that mTBI increases (1) the amount of microglia (iba-1) activated by the pro-inflammatory pathway (CD86); (2) the level of pro-inflammatory cytokines IL1ß and IL6; and (3) CB1R activity. CONCLUSION: Overall, the results of this study indicate that mTBI induces a sustained neuroinflammatory response.

Synaptamide Modulates Astroglial Activity in Mild Traumatic Brain Injury.

At present, the study of the neurotropic activity of polyunsaturated fatty acid ethanolamides (N-acylethanolamines) is becoming increasingly important. N-docosahexaenoylethanolamine (synaptamide, DHEA) is a highly active metabolite of docosahexaenoic acid (DHA) with neuroprotective, synaptogenic, neuritogenic, and anti-inflammatory properties in the nervous system. Synaptamide tested in the present study was obtained using a chemical modification of DHA isolated from squid Berryteuthis magister liver. The results of this study demonstrate the effects of synaptamide on the astroglial response to injury in the acute (1 day) and chronic (7 days) phases of mild traumatic brain injury (mTBI) development. HPLC-MS study revealed several times increase of synaptamide concentration in the cerebral cortex and serum of experimental animals after subcutaneous administration (10 mg/kg/day). Using immunohistochemistry, it was shown that synaptamide regulates the activation of GFAP- and S100ß-positive astroglia, reduce nNOS-positive immunostaining, and stimulates the secretion of neurotrophin BDNF. Dynamics of superoxide dismutase production in synaptamide treatment confirm the antioxidant efficacy of the test compound. We found a decrease in TBI biomarkers such as GFAP, S100ß, and IL-6 in the blood serum of synaptamide-treated experimental animals using Western blot analysis. The results indicate the high therapeutic potential of synaptamide in reducing the severity of the brain damage consequences.

Synaptamide Improves Cognitive Functions and Neuronal Plasticity in Neuropathic Pain.

Neuropathic pain arises from damage or dysfunction of the peripheral or central nervous system and manifests itself in a wide variety of sensory symptoms and cognitive disorders. Many studies demonstrate the role of neuropathic pain-induced neuroinflammation in behavioral disorders. For effective neuropathic pain treatment, an integrative approach is required, which simultaneously affects several links of pathogenesis. One promising candidate for this role is synaptamide (N-docosahexaenoylethanolamine), which is an endogenous metabolite of docosahexaenoic acid. In this study, we investigated the activity of synaptamide on mice behavior and hippocampal plasticity in neuropathic pain induced by spared nerve injury (SNI). We found a beneficial effect of synaptamide on the thermal allodynia and mechanical hyperalgesia dynamics. Synaptamide prevented working and long-term memory impairment. These results are probably based on the supportive effect of synaptamide on SNI-impaired hippocampal plasticity. Nerve ligation caused microglia activation predominantly in the contralateral hippocampus, while synaptamide inhibited this effect. The treatment reversed dendritic tree degeneration, dendritic spines density reduction on CA1-pyramidal neurons, neurogenesis deterioration, and hippocampal long-term potentiation (LTP) impairment. In addition, synaptamide inhibits changes in the glutamatergic receptor expression. Thus, synaptamide has a beneficial effect on hippocampal functioning, including synaptic plasticity and hippocampus-dependent cognitive processes in neuropathic pain.

Anti-Inflammatory Activity of N-Docosahexaenoylethanolamine and N-Eicosapentaenoylethanolamine in a Mouse Model of Lipopolysaccharide-Induced Neuroinflammation.

The search for methods of cognitive impairment treatment and prevention in neurological and neurodegenerative diseases is an urgent task of modern neurobiology. It is now known that various diseases, accompanied by dementia, exhibit a pronounced neuroinflammation. Considering the significant docosahexaenoic and eicosapentaenoic polyunsaturated fatty acids' therapeutic potential, we decided to investigate and compare anti-inflammatory activity of their N-acylethanolamine derivatives. As a result, we found that both N-docosahexaenoylethanolamine (synaptamide) and N-eicosapentaenoylethanolamine (EPEA) prevents an LPS-mediated increase in the proinflammatory cytokines TNF-α and IL-6 production in the SIM-A9 microglia culture. In an in vivo experiment, synaptamide reversed an increase in LPS-mediated hippocampal TNF-α and IL-1ß, but EPEA did not. However, both compounds contributed to the microglia polarization towards the M2-phenotype. Synaptamide, rather than EPEA, inhibited the Iba-1-positive microglia staining area increase. However, both synaptamide and EPEA prevented the LPS-mediated astrogliosis. A study of BDNF immunoreactivity showed that synaptamide, but not EPEA, reversed an LPS-mediated decrease in BDNF production. Despite the more pronounced anti-inflammatory activity of synaptamide, both compounds were effective in maintaining a normal level of hippocampal long-term potentiation in neuroinflammation. The results indicate a high therapeutic potential for both compounds. However, some tests have shown higher activity of synaptamide compared to EPEA.

N-Docosahexaenoylethanolamine Attenuates Neuroinflammation and Improves Hippocampal Neurogenesis in Rats with Sciatic Nerve Chronic Constriction Injury.

Chronic neuropathic pain is a condition that causes both sensory disturbances and a variety of functional disorders, indicating the involvement of various brain structures in pain pathogenesis. One of the factors underlying chronic neuropathic pain is neuroinflammation, which is accompanied by microglial activation and pro-inflammatory factor release. N-docosahexaenoylethanolamine (DHEA, synaptamide) is an endocannabinoid-like metabolite synthesized endogenously from docosahexaenoic acid. Synaptamide exhibits anti-inflammatory activity and improves neurite outgrowth, neurogenesis, and synaptogenesis within the hippocampus. This study aims to evaluate the effects of synaptamide obtained by the chemical modification of DHA, extracted from the Far Eastern raw material Berryteuthis magister on neuroinflammatory response and hippocampal neurogenesis changes during neuropathic pain. The study of microglial protein and cytokine concentrations was performed using immunohistochemistry and ELISA. The brain lipid analysis was performed using the liquid chromatography-mass spectrometry technique. Behavioral experiments showed that synaptamide prevented neuropathic pain-associated sensory and behavioral changes, such as thermal allodynia, impaired locomotor activity, working and long-term memory, and increased anxiety. Synaptamide attenuated microglial activation, release of proinflammatory cytokines, and decrease in hippocampal neurogenesis. Lipid analysis revealed changes in the brain N-acylethanolamines composition and plasmalogen concentration after synaptamide administration. In conclusion, we show here that synaptamide may have potential for use in preventing or treating neuropathic cognitive pain and emotional effects.

N-Docosahexanoylethanolamine Reduces Microglial Activation and Improves Hippocampal Plasticity in a Murine Model of Neuroinflammation.

Chronic neuroinflammation is a common pathogenetic link in the development of various neurological and neurodegenerative diseases. Thus, a detailed study of neuroinflammation and the development of drugs that reduce or eliminate the negative effect of neuroinflammation on cognitive processes are among the top priorities of modern neurobiology. N-docosahexanoylethanolamine (DHEA, synaptamide) is an endogenous metabolite and structural analog of anandamide, an essential endocannabinoid produced from arachidonic acid. Our study aims to elucidate the pharmacological activity of synaptamide in lipopolysaccharide (LPS)-induced neuroinflammation. Memory deficits in animals were determined using behavioral tests. To study the effects of LPS (750 µg/kg/day, 7 days) and synaptamide (10 mg/kg/day, 7 days) on synaptic plasticity, long-term potentiation was examined in the CA1 area of acute hippocampal slices. The Golgi-Cox method allowed us to assess neuronal morphology. The production of inflammatory factors and receptors was assessed using ELISA and immunohistochemistry. During the study, functional, structural, and plastic changes within the hippocampus were identified. We found a beneficial effect of synaptamide on hippocampal synaptic plasticity and morphological characteristics of neurons. Synaptamide treatment recovered hippocampal neurogenesis, suppressed microglial activation, and significantly improved hippocampus-dependent memory. The basis of the phenomena described above is probably the powerful anti-inflammatory activity of synaptamide, as shown in our study and several previous works.

Hippocampal Neurogenesis in Conditions of Chronic Stress Induced by Sciatic Nerve Injury in the Rat.

The dentate gyrus of the hippocampus is the primary location of adult neurogenesis, which is affected by a variety of external and internal factors, including activity of surrounding glial cells. This study concerns alterations in hippocampal neurogenesis and changes in activity of both proinflammatory and neuroprotective microglia/macrophages after sciatic nerve injury in the rat. Here, we demonstrated that the chronic pain induced by a peripheral nerve injury manifests in the hippocampus by a decrease in proliferation (PCNA+) and neurogenesis (DCX+), an increase in proinflammatory cytokines (CD86+), and a reduction in neuroprotective (CD163+) microglia/macrophages. We suggest that a pathological increase microglia/macrophage activity is the cause of neurogenesis suppression observed in chronic neuropathic pain.

Neuropathic Pain Causes a Decrease in the Dendritic Tree Complexity of Hippocampal CA3 Pyramidal Neurons.

The International Pain Association defines neuropathic pain as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage." Recent studies show that chronic neuropathic pain causes both morphological and functional changes within brain structures. Due to the impact of supraspinal centers on pain signal processing, patients with chronic pain often suffer from depression, anxiety, memory impairment, and learning disabilities. Changes in hippocampal neuronal and glial plasticity can play a substantial role in the development of these symptoms. Given the special role of the CA3 hippocampal area in chronic stress reactions, we suggested that this region may undergo significant morphological changes as a result of persistent pain. Since the CA3 area is involved in the implementation of hippocampus-dependent memory, changes in the neuronal morphology can cause cognitive impairment observed in chronic neuropathic pain. This study aimed to elucidate the structural and plastic changes within the hippocampus associated with dendritic tree atrophy of CA3 pyramidal neurons in mice with chronic sciatic nerve constriction. Behavioral testing revealed impaired working and long-term memory in mice with a chronic constriction injury. Using the Golgi-Cox method, we revealed a decrease in the number of branches and dendritic length of CA3 pyramidal neurons. The dendritic spine number was decreased, predominantly due to a reduction in mushroom spines. An -immunohistochemical study showed changes in astro- and microglial activity, which could affect the morphology of neurons both directly and indirectly via the regulation of neurotrophic factor synthesis. Using ELISA, we found a decrease in brain-derived neurotrophic factor production and an increase in neurotrophin-3 production. Morphological and biochemical changes in the CA3 area are accompanied by impaired working and long-term memory of animals. Thus, we can conclude that morphological and biochemical changes within the CA3 hippocampal area may underlie the cognitive impairment in neuropathic pain.

Developmental excitatory-to-inhibitory GABA polarity switch is delayed in Ts65Dn mice, a genetic model of Down syndrome.

Down syndrome (DS) is the most frequent genetic cause of developmental abnormalities leading to intellectual disability. One notable phenomenon affecting the formation of nascent neural circuits during late developmental periods is developmental switch of GABA action from depolarizing to hyperpolarizing mode. We examined properties of this switch in DS using primary cultures and acute hippocampal slices from Ts65Dn mice, a genetic model of DS. Cultures of DIV3-DIV13 Ts65Dn and control normosomic (2 N) neurons were loaded with FURA-2 AM, and GABA action was assessed using local applications. In 2 N cultures, the number of GABA-activated cells dropped from ~100% to 20% between postnatal days 3-13 (P3-P13) reflecting the switch in GABA action polarity. In Ts65Dn cultures, the timing of this switch was delayed by 2-3 days. Next, microelectrode recordings of multi-unit activity (MUA) were performed in CA3 slices during bath application of the GABAA agonist isoguvacine. MUA frequency was increased in P8-P12 and reduced in P14-P22 slices reflecting the switch of GABA action from excitatory to inhibitory mode. The timing of this switch was delayed in Ts65Dn by approximately 2 days. Finally, frequency of giant depolarizing potentials (GDPs), a form of primordial neural activity, was significantly increased in slices from Ts65Dn pups at P12 and P14. These experimental evidences show that GABA action polarity switch is delayed in Ts65Dn model of DS, and that these changes lead to a delay in maturation of nascent neural circuits. These alterations may affect properties of neural circuits in adult animals and, therefore, represent a prospective target for pharmacotherapy of cognitive impairment in DS.

Acute neuroinflammation provokes intracellular acidification in mouse hippocampus.

BACKGROUND: Maintaining pH levels within the physiological norm is an important component of brain homeostasis. However, in some pathological or physiological conditions, the capacity of the pH regulatory system could be overpowered by various factors resulting in a transient or permanent alteration in pH levels. Such changes are often observed in pathological conditions associated with neuroinflammation. We hypothesized that neuroinflammation itself is a factor affecting pH levels in neural tissue. To assess this hypothesis, we examined the effects of acute LPS-induced neuroinflammation on intra- and extracellular pH (pHi and pHo) levels in the CA1 region of mouse hippocampus. METHODS: Acute neuroinflammation was induced using two approaches: (1) in vivo by i.p. injections of LPS (5 mg/kg) and (2) in vitro by incubating hippocampal slices of naïve animals in the LPS-containing media (1 µg/mL, 1 h at 35 °C). Standard techniques were used to prepare hippocampal slices. pHi was measured using ratiometric pH-sensitive fluorescent dye BCECF-AM. pHo was assessed using calibrated pH-sensitive micropipettes. The presence of neuroinflammation was verified with immunohistochemistry (IL-1ß and Iba1) and ELISA (IL-1ß and TNF-α). RESULTS: A significant reduction of pHi was observed in the slices of the LPS-injected 3-month-old (LPS 7.13 ± 0.03; Sal 7.22 ± 0.03; p = 0.043, r = 0.43) and 19-month-old (LPS 6.78 ± 0.08; Sal 7.13 ± 0.03; p = 0.0001, r = 0.32) mice. In contrast, the levels of pHo within the slice, measured in 19-month-old animals, were not affected (LPS 7.27 ± 0.02; Sal 7.26 ± 0.02; p = 0.6, r = 0.13). A reduction of pHi was also observed in the LPS-treated slices during the interval 3.5-7 h after the LPS exposure (LPS 6.92 ± 0.07; Veh 7.28 ± 0.05; p = 0.0001, r = 0.46). CONCLUSIONS: Acute LPS-induced neuroinflammation results in a significant intracellular acidification of the CA1 neurons in mouse hippocampus, while the pHo remains largely unchanged. Such changes may represent a specific protective reaction of neural tissue in unfavorable external conditions or be a part of the pathological process.

Anti-inflammatory and anti-apoptotic activity of synaptamide improves the morphological state of neurons in traumatic brain injury.

Traumatic brain injuries (TBI) of varying severity are becoming more frequent all over the world. The process of neuroinflammation, in which macrophages and microglia are key players, underlies all types of brain damage. The present study focuses on evaluating the therapeutic potential of N-docosahexaenoylethanolamine (DHEA, synaptamide), which is an endogenous metabolite of docosahexaenoic acid in traumatic brain injury. Previously, several in vitro and in vivo models have shown significant anti-neuroinflammatory and synaptogenic activity of synaptamide. The results of the present study show that synaptamide by subcutaneous administration (10 mg/kg/day, 7 days) exerts anti-inflammatory and anti-apoptotic effects in the thalamus and cerebral cortex of experimental animals (male C57BL/6 mice). Were analyzed the dynamics of changes in the activity of Iba-1- and CD68-positive microglia/macrophages, the level of production of pro-inflammatory cytokines (IL1ß, IL6, TNFα) and pro-apoptotic proteins (Bad, Bax), the expression of pro- and anti-inflammatory markers (CD68, CD206, arg-1). ATF3 transcription factor distribution and neuronal state in the thalamus and cerebral cortex of animals with craniotomy, traumatic brain injury, and therapy are quantitatively assessed. The obtained data showed that synaptamide: (1) has no effect on the total pool of microglia/macrophages; (2) inhibits the activity of pro-inflammatory microglia/macrophages and cytokines they produce; (3) increases the expression of CD206 but not arg-1; (4) has anti-apoptotic effect and (5) improves the morphological state of neurons. The results obtained confirm the high therapeutic potential of synaptamide in the therapy of traumatic brain injury.

Synaptamide modulates glial and neurotransmitter activity in the spinal cord during neuropathic pain.

N-docosahexaenoylethanolamine, or synaptamide, is an endogenous metabolite of docosahexaenoic acid that is known for synaptogenic and neurogenic effects. In our previous studies we have shown that synaptamide attenuates neuropathic pain, facilitates remyelination, and reduces neuroinflammation after the chronic constriction injury (CCI) of the sciatic nerve in rats. In the current study, we show that daily synaptamide administration (4 mg/kg/day) within 14 days post-surgery: (1) decreases micro- and astroglia activity in the dorsal and ventral horns of the lumbar spinal cord; (2) modulates pro-inflammatory (IL1ß, IL6) and anti-inflammatory (IL4, IL10) cytokine level in the serum and spinal cord; (3) leads to a rise in synaptamide and anandamide concentration in the spinal cord; (4) enhances IL10, CD206 and N-acylethanolamine-hydrolyzing acid amidase synthesis in macrophage cell culture following LPS-induced inflammation. Thus, the ability of synaptamide to modulate glial and cytokine activity indicates its potential for implementation in the treatment peripheral nerve injury.

Anti-inflammatory Effect of Polyunsaturated Fatty Acid N-Acylethanolamines Mediated by Macrophage Activity In Vitro and In Vivo.

In recent years, there has been increasing interest in studying the anti-inflammatory activity of polyunsaturated fatty acid ethanolamides (N-acylethanolamines, NAE), which are highly active lipid mediators. The results of this study demonstrate that a dietary supplement (DS) of fatty acid-derived NAEs reduces LPS-induced inflammation. The processes of cell proliferation, as well as the dynamics of Iba-1-, CD68-, and CD163-positive macrophage activity within the thymus and spleen were studied. The production of pro-inflammatory cytokines (TNF, IL1ß, IL6, and INFγ), ROS, NO, and nitrites was evaluated in the blood serum, thymus, and LPS-stimulated RAW264.7 mouse macrophages. In vitro and in vivo experiments have shown that DS (1) prevents LPS-induced changes in the morphological structure of the thymus and spleen; (2) levels out changes in cell proliferation; (3) inhibits the activity of Iba-1 and CD68-positive cells; (4) reduces the production of pro-inflammatory cytokines (TNF, IL1ß, IL6, and INFγ), ROS, and CD68; and (5) enhances the activity of CD-163-positive cells. In general, the results of this study demonstrate the complex effect of DS on inflammatory processes in the central and peripheral immune systems.

Fatty Acid-Derived N-acylethanolamines Dietary Supplementation Attenuates Neuroinflammation and Cognitive Impairment in LPS Murine Model.

Neuroinflammation plays a critical role in the pathogenesis of most neurological and neurodegenerative diseases and therefore represents a potential therapeutic target. In this regard, accelerating the resolution process in chronic neuroinflammation may be an effective strategy to deal with the cognitive consequences of neuropathology and generalized inflammatory processes. N-acylethanolamine (NAE) derivatives of fatty acids, being highly active lipid mediators, possess pro-resolving activity in inflammatory processes and are promising agents for the suppression of neuroinflammation and its consequences. This paper is devoted to a study of the effects played by dietary supplement (DS), containing a composition of fatty acid-derived NAEs, obtained from squid Berryteuthis magister, on the hippocampal neuroinflammatory and memory processes. By detecting the production of pro-inflammatory cytokines and glial markers, a pronounced anti-inflammatory activity of DS was demonstrated both in vitro and in vivo. DS administration reversed the LPS-induced reduction in hippocampal neurogenesis and memory deterioration. LC-MS analysis revealed an increase in the production of a range of NAEs with well-documented anti-inflammatory activity in response to the administered lipid composition. To conclude, we found that tested DS suppresses the neuroinflammatory response by reducing glial activation, positively regulates neural progenitor proliferation, and attenuates hippocampal-dependent memory impairment.

Modulation of Hippocampal Astroglial Activity by Synaptamide in Rats with Neuropathic Pain.

The present study demonstrates that synaptamide (N-docosahexaenoylethanolamine), an endogenous metabolite of docosahexaenoic acid, when administered subcutaneously (4 mg/kg/day, 14 days), exhibits analgesic activity and promotes cognitive recovery in the rat sciatic nerve chronic constriction injury (CCI) model. We analyzed the dynamics of GFAP-positive astroglia and S100ß-positive astroglia activity, the expression of nerve growth factor (NGF), and two subunits of the NMDA receptor (NMDAR1 and NMDAR2A) in the hippocampi of the experimental animals. Hippocampal neurogenesis was evaluated by immunohistochemical detection of DCX. Analysis of N-acylethanolamines in plasma and in the brain was performed using the liquid chromatography-mass spectrometry technique. In vitro and in vivo experiments show that synaptamide (1) reduces cold allodynia, (2) improves working memory and locomotor activity, (3) stabilizes neurogenesis and astroglial activity, (4) enhances the expression of NGF and NMDAR1, (5) increases the concentration of Ca2+ in astrocytes, and (6) increases the production of N-acylethanolamines. The results of the present study demonstrate that synaptamide affects the activity of hippocampal astroglia, resulting in faster recovery after CCI.

N-docosahexaenoylethanolamine reduces neuroinflammation and cognitive impairment after mild traumatic brain injury in rats.

At present, there is a growing interest in the study of the neurotropic activity of polyunsaturated fatty acids ethanolamides (N-acylethanolamines). N-docosahexaenoylethanolamine (DHEA, synaptamide) is an endogenous metabolite and structural analogue of anandamide, a widely studied endocannabinoid derived from arachidonic acid. The results of this study demonstrate that DHEA, when administered subcutaneously (10 mg/kg/day, 7 days), promotes cognitive recovery in rats subjected to mild traumatic brain injury (mTBI). In the cerebral cortex of experimental animals, we analyzed the dynamics of Iba-1-positive microglia activity changes and the expression of pro-inflammatory markers (IL1ß, IL6, CD86). We used immortalized mouse microglial cells (SIM-A9) to assess the effects of DHEA on LPS-induced cytokines/ROS/NO/nitrite, as well as on CD206 (anti-inflammatory microglia) and the antioxidant enzyme superoxide dismutase (SOD) production. In vivo and in vitro experiments showed that DHEA: (1) improves indicators of anxiety and long-term memory; (2) inhibits the pro-inflammatory microglial cells activity; (3) decrease the level of pro-inflammatory cytokines/ROS/NO/nitrites; (4) increase CD206 and SOD production. In general, the results of this study indicate that DHEA has a complex effect on the neuroinflammation processes, which indicates its high therapeutic potential.