Production and release of docosahexaenoic acid by differentiated rat brain astrocytes

Therapeutic potential of clinically proven natural products in the management of dementia

Dementia is a common neurodegenerative disorder connected to damage to nerve cells in the brain. Although some conventional drugs are available for dementia treatments and are still sanctified for dementia patients, their short- and long-term side effects and other limitations make treating patients more challenging. The authors aimed to explain novel options for treating dementia with natural products and unravel some clinically proven natural products. This article systematically reviewed recent studies that have investigated the role of natural products and their bioactive compounds for dementia. PubMed Central, Scopus, and Google Scholar databases of articles were collected, and abstracts were reviewed for relevance to the subject matter.In this review, we provide mechanistic insights of clinically validated natural products, including like- Yokukansan, Souvenaid, BDW, Hupergene, Bacopa monnier, Omega-3, Tramiprostate and Palmitoylethanolamide with which have therapeutic efficacy against dementia in the management of dementia. As shown by studies, certain natural ingredients could be used to treat and prevent dementia. We strongly believe that the medicinal plants and phytoconstituents alone or in combination with other compounds would be effective treatments against dementia with lesser side effects as compared to currently available treatments. Moreover, these products should be studied further in order to develop novel dementia medications.

Effectiveness of omega-3 fatty acid supplementation in patients with Alzheimer disease: A systematic review and meta-analysis

INTRODUCTION

Alzheimer disease (AD) is a neurodegenerative disease characterised by progressive dementia associated with global cognitive dysfunction.

METHODS

We conducted a systematic review and meta-analysis of clinical trials evaluating omega-3 supplementation in patients with AD.

OBJECTIVE

To determine if there is scientific evidence of the effectiveness of omega-3 supplementation in improving cognitive function in patients with AD.

SEARCH STRATEGY

We included only randomised controlled trials (RCTs) from the following databases: Medline, Cochrane Central, Cinahl, and LILACS. An electronic search was also conducted using Google Scholar.

STUDY SELECTION

Six articles met the eligibility criteria. The risk of bias was assessed following the Cochrane method.

CONCLUSION

There is no consistent evidence to support the effectiveness of omega-3 supplementation in improving cognitive function in AD patients in the short and medium term.

Involvement of GPR40, a long-chain free fatty acid receptor, in the production of central post-stroke pain after global cerebral ischemia

Central post-stroke pain (CPSP), one of the complications of cerebral ischemia and neuropathic pain syndrome, is associated with specific somatosensory abnormalities. Although CPSP is a serious problem, detailed underlying mechanisms and standard treatments for CPSP are not well established. In this study, we assessed the role of GPR40, a long-chain fatty acid receptor, showing anti-nociceptive effects, in CPSP. We also examined the role of astrocytes in CPSP due to their effects in mediating the release of polyunsaturated fatty acids, which act as potential GPR40 ligands. The aim of this study was to determine the interactions between CPSP and astrocyte/GPR40 signaling. Male ddY mice were subjected to 30 min of bilateral carotid artery occlusion (BCAO). The development of hind paw mechanical hyperalgesia was measured after BCAO using the von Frey test. Neuronal damage was estimated by histological analysis on day 3 after BCAO. The thresholds for hind paw mechanical hyperalgesia were significantly decreased on days 1-28 after BCAO when compared with those of pre-BCAO assessments. BCAO-induced mechanical hyperalgesia was significantly decreased by intracerebroventricular injection of docosahexaenoic acid or GW9508, a GPR40 agonist; furthermore, these effects were reversed by GW1100, a GPR40 antagonist. The expression levels of glial fibrillary acidic protein, an astrocytic marker, and some free fatty acids were significantly decreased 5h after BCAO, although no effects of BCAO were noted on hypothalamic GPR40 protein expression. Our data show that BCAO-induced mechanical hyperalgesia is possible to be regulated by astrocyte activation and stimulation of GPR40 signaling.

Towards a nutritional approach for prevention of Alzheimer's disease: Biochemical and cellular aspects

Alzheimer's disease (AD) is a major public health concern in all countries. Although the precise cause of AD is still unknown, a growing body of evidence supports the notion that soluble amyloid beta-peptide (Abeta) may be the proximate cause of synaptic injuries and neuronal death early in the disease. AD patients display lower levels of docosahexaenoic acid (DHA, C22:6 ; n-3) in plasma and brain tissues as compared to age-matched controls. Furthermore, epidemiological studies suggest that high DHA intake might have protective properties against neurodegenerative diseases. These observations are supported by in vivo studies showing that DHA-rich diets limits the synaptic loss and cognitive defects induced by Abeta peptide. Although the molecular basis of these neuroprotective effects remains unknown, several mechanisms have been proposed such as (i) regulation of the expression of potentially protective genes, (ii) activation of anti-inflammatory pathways, (iii) modulation of functional properties of the synaptic membranes along with changes in their physicochemical and structural features.

Half-lives of docosahexaenoic acid in rat brain phospholipids are prolonged by 15 weeks of nutritional deprivation of n-3 polyunsaturated fatty acids

Male rat pups (21 days old) were placed on a diet deficient in n-3 polyunsaturated fatty acids (PUFAs) or on an n-3 PUFA adequate diet containing alpha-linolenic acid (alpha-LNA; 18 : 3n-3). After 15 weeks on a diet, [4,5-3H]docosahexaenoic acid (DHA; 22 : 6n-3) was injected into the right lateral cerebral ventricle, and the rats were killed at fixed times over a period of 60 days. Compared with the adequate diet, 15 weeks of n-3 PUFA deprivation reduced plasma DHA by 89% and brain DHA by 37%; these DHA concentrations did not change thereafter. In the n-3 PUFA adequate rats, DHA loss half-lives, calculated by plotting log10 (DHA radioactivity) against time after tracer injection, equaled 33 days in total brain phospholipid, 23 days in phosphatidylcholine, 32 days in phosphatidylethanolamine, 24 days in phosphatidylinositol and 58 days in phosphatidylserine; all had a decay slope significantly greater than 0 (p < 0.05). In the n-3 PUFA deprived rats, these half-lives were prolonged twofold or greater, and calculated rates of DHA loss from brain, Jout, were reduced. Mechanisms must exist in the adult rat brain to minimize DHA metabolic loss, and to do so even more effectively in the face of reduced n-3 PUFA availability for only 15 weeks.

Comparison of 20-, 22-, and 24-carbon n-3 and n-6 polyunsaturated fatty acid utilization in differentiated rat brain astrocytes

Astrocytes convert n-6 fatty acids primarily to arachidonic acid (20:4n-6), whereas n-3 fatty acids are converted to docosapentaenoic (22:5n-3) and docosahexaenoic (22:6n-3) acids. The utilization of 20-, 22- and 24-carbon n-3 and n-6 fatty acids was compared in differentiated rat astrocytes to determine the metabolic basis for this difference. The astrocytes retained 81% of the arachidonic acid ([(3)H]20:4n-6) uptake and retroconverted 57% of the docosatetraenoic acid ([3-(14)C]22:4n-6) uptake to 20:4n-6. By contrast, 68% of the eicosapentaenoic acid ([(3)H]20:5n-3) uptake was elongated, and only 9% of the [3-(14)C]22:5n-3 uptake was retroconverted to 20:5n-3. Both tetracosapentaenoic acid ([3-(14)C]24:5n-3) and tetracosatetraenoic acid ([3-(14)C]24:4n-6) were converted to docosahexaenoic acid (22:6n-3) and 22:5n-6, respectively. Therefore, the difference in the n-3 and n-6 fatty acid products formed is due primarily to differences in the utilization of their 20- and 22-carbon intermediates. This metabolic difference probably contributes to the preferential accumulation of docosahexaenoic acid in the brain.