Promoting Neurovascular Recovery in Aged Mice after Ischemic Stroke - Prophylactic Effect of Omega-3 Polyunsaturated Fatty Acids
Cai Mengfei1, Zhang Wenting1,*, Weng Zhongfang2, Stetler R. Anne1,2,3, Jiang Xiaoyan2, Shi Yejie2,3, Gao Yanqin1,2,*, Chen Jun1,2,3,*
1State Key Laboratory of Medical Neurobiology and Institute of Brain Sciences, and Collaborative Innovation Center, Fudan University, Shanghai 200032, China 2Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA 3Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, PA 15261, USA
The aged population is among the highest at risk for ischemic stroke, yet most stroke patients of advanced ages (>80 years) are excluded from access to thrombolytic treatment by tissue plasminogen activator, the only FDA approved pharmacological therapy for stroke victims. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) robustly alleviate ischemic brain injury in young adult rodents, but have not yet been studied in aged animals. This study investigated whether chronic dietary supplementation of n-3 PUFAs protects aging brain against cerebral ischemia and improves long-term neurological outcomes. Aged (18-month-old) mice were administered n-3 PUFA-enriched fish oil in daily chow for 3 months before and up to 8 weeks after 45 minutes of transient middle cerebral artery occlusion (tMCAO). Sensorimotor outcomes were assessed by cylinder test and corner test up to 35 days and brain repair dynamics evaluated immunohistologically up to 56 days after tMCAO. Mice receiving dietary supplementation of n-3 PUFAs for 3 months showed significant increases in brain ratio of n-3/n-6 PUFA contents, and markedly reduced long-term sensorimotor deficits and chronic ischemic brain tissue loss after tMCAO. Mechanistically, n-3 PUFAs robustly promoted post-ischemic angiogenesis and neurogenesis, and enhanced white matter integrity after tMCAO. The Pearson linear regression analysis revealed that the enhancement of neurogenesis and white matter integrity both correlated positively with improved sensorimotor activities after tMCAO. This study demonstrates that prophylactic dietary supplementation of n-3 PUFAs effectively improves long-term stroke outcomes in aged mice, perhaps by promoting post-stroke brain repair processes such as angiogenesis, neurogenesis, and white matter restoration.
Cai Mengfei,Zhang Wenting,Weng Zhongfang, et al. Promoting Neurovascular Recovery in Aged Mice after Ischemic Stroke - Prophylactic Effect of Omega-3 Polyunsaturated Fatty Acids[J]. Aging and disease,
2017, 8(5): 531-545.
Figure 1. Lipid profiles are altered in the forebrains of aged mice by dietary PUFA supplementation
Mice were maintained on a low n-3 PUFA (N3L) or high n-3 PUFA (N3H) diet for 3 months, and forebrains were then processed for lipid analysis. (A) Lipid profiles in mouse forebrains expressed as the percent of total fatty acids (TFA), and included profiles of saturated fatty acids (SFA), mono-unsaturated fatty acids (MUFA), and poly-unsaturated fatty acids (PUFA). (B) The ratio of forebrain n-3 to n-6 fatty acids increased in N3H-fed mice. (C) Specific n-3 PUFAs content expressed as pmol/mg; the n-3 PUFAs include α-linolenic acid (ALA), docosapentaenoic acid (DPA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). (D) Specific n-6 PUFAs content expressed as pmol/mg: the n-6 PUFAs include arachidonic acid (AA), docosatetraenoic acid (DTA), dihomo-γ-linolenic acid (DGLA) and γ-linoleic acid (GLA). Data are mean ± SEM, n=4 per group; *p≤0.05, **p≤0.01 vs. N3L.
Figure 2. Dietary n-3 PUFAs supplementation protects against long-term behavioral deficits and infarct induced by ischemic brain injury in aged mice
(A) Diagram of the experimental timeline. 18-month-old (18 mo) mice were fed either the standard chow or chow supplemented with n-3 PUFAs enriched fish oil, then subjected to 45 min of transient MCAO at 21 months (21 mo) of age. After MCAO, the mice were maintained on the same diet as prior to MCAO until the end of the study (56 days after MCAO). Pre-training for behavioral tests occurred 3 days before 45 min transient MCAO or sham operation. BrdU was injected daily starting 3 days after MCAO through day 10 after MCAO. Sensorimotor function was evaluated up to 35 days after MCAO. Mice were sacrificed 56 days after MCAO for histological assessments. (B) Regional cerebral blood flow measured by laser Doppler during and after MCAO showed no difference between N3L and N3H groups for the duration and extent of ischemic induction. (C, D) Tissue loss from N3L- and N3H-fed mice 56 days after MCAO was measured by MAP2 immunostaining. Representative images of MAP2 staining at 56 days after MCAO are shown, where the dashed lines illustrate chronic brain infarct (MAP2-negative area). Scale bar=1mm. (E) The corner test and cylinder test performance over 35 days after MCAO demonstrated impairments in both groups of MCAO mice. The N3H-fed mice showed significantly improved performance compared to ischemic mice fed the N3L diet. All data are presented as mean ± SEM, n=7 per group, #p≤0.05, ##p≤0.01 vs.; *p≤0.05, **p≤0.01 vs. N3L tMCAO.
Figure 3. Dietary n-3 PUFAs enhances angiogenesis after MCAO in aged mice
Mice were injected with BrdU daily over 3-10 days following 45 min MCAO, then processed for immunohistology for BrdU and CD31 at 56 days following MCAO. (A) Representative images of CD31 and BrdU double-labeling within the peri-infart region (striatum) of vehicle and n-3 PUFAs treated brains at 56 days after MCAO. Arrow: BrdU+/CD31+ cells. Scale bar=50 μm. (B) Representative high power confocal images of BrdU+/CD31+ co-localization in the striatum at 56 days after MCAO. Scale bar=10 μm. (C) An image stained with MAP2 to designate the infarct area. Analysis of angiogenesis was derived from the regions marked by the blue boxes in the peri-infarct striatum. (D-F) Quantification of post-stroke generated (BrdU+/CD31+) vessels, vessel (CD31+) length, and number of all vessels (CD31+ vessels) at 56 days after cerebral ischemia. Data are presented as mean ± SEM, N3L group, n = 5; N3H group, n=6. *p≤0.05 vs. N3L, #p≤0.05, ##p≤0.01 vs. sham. (G, H) Pearson linear regression analysis was performed to correlate the performance of corner test (G) and cylinder test (H) at 21-35 days after MCAO with the number of BrdU+/CD31+ cells in striatum at 56 days after MCAO.
Figure 4. Dietary supplementation of n-3 PUFAs increase the presence of matured neural progenitor cells after ischemia in aged mice
(A) Representative images of mature neurons (NeuN+, red) and BrdU+ (green) cells in the striatum after MCAO. Scale bar=50 μm. Arrow: NeuN+/BrdU+ cells. (B) Quantification of BrdU+/NeuN+ cells at 56 days after cerebral ischemia. Data are presented as mean ± SEM, n = 5-6 mice per group at each time point. ***p≤0.001 vs. N3L. (C, D) Pearson linear regression analysis was performed to correlate the performance of corner test (C) and cylinder test (D) at 21-35 days after MCAO with the number of NeuN+/BrdU+ cells in striatum at 56 days after MCAO. N3L group, n = 5; N3H group, n=6.
Figure 5. n-3 PUFAs supplementation decreases demyelination after MCAO in aged mice
(A) Representative images of SMI-32 and MBP double staining in striatum (STR) and in corpus callosum (CC) of aged mice 56 days after MCAO. The dashed white line indicates the border between the cortex and corpus callosum. Scale bar=50 μm. (B) Diagram to indicate the infarct core, infarct border and peri-infarct regions. The blue and purple boxes indicate the areas used for histological assessments for STR and CC, respectively. (C, D) Quantification of SMI-32/MBP ratio in the striatum (C) and corpus callosum (D). Data are presented as mean ± SEM, n = 5 per group, **p≤0.01 vs. N3L. ##p≤0.01 vs. sham. (E-H) Pearson linear regression analysis was performed to correlate asymmetric rate of forelimb use in corner test (E, G) and cylinder test (F, H) at 21-35 days after MCAO with the ratio of SMI-32/MBP in STR (E, F) or CC (G, H) 56 days after MCAO. N3L group, n = 5; N3H group, n=6.
Fonarow GC, Smith EE, Saver JL, Reeves MJ, Bhatt DL, Grau-Sepulveda MV, et al. (2011). Timeliness of tissue-type plasminogen activator therapy in acute ischemic stroke: patient characteristics, hospital factors, and outcomes associated with door-to-needle times within 60 minutes. Circulation, 123: 750-758.
Arora R, Salamon E, Katz JM, Cox M, Saver JL, Bhatt DL, et al. (2016). Use and Outcomes of Intravenous Thrombolysis for Acute Ischemic Stroke in Patients >/=90 Years of Age. Stroke, 47: 2347-2354.
Emberson J, Lees KR, Lyden P, Blackwell L, Albers G, Bluhmki E, et al. (2014). Effect of treatment delay, age, and stroke severity on the effects of intravenous thrombolysis with alteplase for acute ischaemic stroke: a meta-analysis of individual patient data from randomised trials. Lancet, 384: 1929-1935.
Hacke W, Kaste M, Bluhmki E, Brozman M, Davalos A, Guidetti D, et al. (2008). Thrombolysis with alteplase 3 to 4.5 hours after acute ischemic stroke. N Engl J Med, 359: 1317-1329.
Mishra NK, Ahmed N, Andersen G, Egido JA, Lindsberg PJ, Ringleb PA, et al. (2010). Thrombolysis in very elderly people: controlled comparison of SITS International Stroke Thrombolysis Registry and Virtual International Stroke Trials Archive. BMJ, 341: c6046.
Perez de la Ossa N, Abilleira S, Dorado L, Urra X, Ribo M, Cardona P, et al. (2016). Access to Endovascular Treatment in Remote Areas: Analysis of the Reperfusion Treatment Registry of Catalonia. Stroke, 47: 1381-1384.
Kokaia Z, Lindvall O (2003). Neurogenesis after ischaemic brain insults. Curr Opin Neurobiol, 13: 127-132
Darsalia V, Heldmann U, Lindvall O, Kokaia Z (2005). Stroke-induced neurogenesis in aged brain. Stroke, 36: 1790-1795.
Lazarov O, Hollands C (2016). Hippocampal neurogenesis: Learning to remember. Prog Neurobiol, 138-140: 1-18.
Amin-Hanjani S, Du X, Pandey DK, Thulborn KR, Charbel FT (2015). Effect of age and vascular anatomy on blood flow in major cerebral vessels. J Cereb Blood Flow Metab, 35: 312-318.
Jin K, Minami M, Xie L, Sun Y, Mao XO, Wang Y, et al. (2004). Ischemia-induced neurogenesis is preserved but reduced in the aged rodent brain. Aging Cell, 3: 373-377.
Popa-Wagner A, Carmichael ST, Kokaia Z, Kessler C, Walker LC (2007). The response of the aged brain to stroke: too much, too soon? Curr Neurovasc Res, 4: 216-227.
Sozmen EG, Rosenzweig S, Llorente IL, DiTullio DJ, Machnicki M, Vinters HV, et al. (2016). Nogo receptor blockade overcomes remyelination failure after white matter stroke and stimulates functional recovery in aged mice. Proc Natl Acad Sci U S A, 113: E8453-E8462.
Brenna JT, Diau GY (2007). The influence of dietary docosahexaenoic acid and arachidonic acid on central nervous system polyunsaturated fatty acid composition. Prostaglandins Leukot Essent Fatty Acids, 77: 247-250.
Yeh YY, Gehman MF, Yeh SM (1993). Maternal dietary fish oil enriches docosahexaenoate levels in brain subcellular fractions of offspring. J Neurosci Res, 35: 218-226.
McNamara RK, Liu Y, Jandacek R, Rider T, Tso P (2008). The aging human orbitofrontal cortex: decreasing polyunsaturated fatty acid composition and associated increases in lipogenic gene expression and stearoyl-CoA desaturase activity. Prostaglandins Leukot Essent Fatty Acids, 78: 293-304.
Yehuda S, Rabinovitz S, Carasso RL, Mostofsky DI (2002). The role of polyunsaturated fatty acids in restoring the aging neuronal membrane. Neurobiol Aging, 23: 843-853.
Cutuli D, De Bartolo P, Caporali P, Laricchiuta D, Foti F, Ronci M, et al. (2014). n-3 polyunsaturated fatty acids supplementation enhances hippocampal functionality in aged mice. Front Aging Neurosci, 6: 220.
Dyall SC, Michael GJ, Michael-Titus AT (2010). Omega-3 fatty acids reverse age-related decreases in nuclear receptors and increase neurogenesis in old rats. J Neurosci Res, 88: 2091-2102.
Titova OE, Sjogren P, Brooks SJ, Kullberg J, Ax E, Kilander L, et al. (2013). Dietary intake of eicosapentaenoic and docosahexaenoic acids is linked to gray matter volume and cognitive function in elderly. Age (Dordr), 35: 1495-1505.
Raji CA, Erickson KI, Lopez OL, Kuller LH, Gach HM, Thompson PM, et al. (2014). Regular fish consumption and age-related brain gray matter loss. Am J Prev Med, 47: 444-451.
Song TJ, Chang Y, Shin MJ, Heo JH, Kim YJ (2015). Low levels of plasma omega 3-polyunsaturated fatty acids are associated with cerebral small vessel diseases in acute ischemic stroke patients. Nutr Res, 35: 368-374.
Zhang W, Wang H, Zhang H, Leak RK, Shi Y, Hu X, et al. (2015). Dietary supplementation with omega-3 polyunsaturated fatty acids robustly promotes neurovascular restorative dynamics and improves neurological functions after stroke. Exp Neurol, 272: 170-180.
Hu X, Zhang F, Leak RK, Zhang W, Iwai M, Stetler RA, et al. (2013). Transgenic overproduction of omega-3 polyunsaturated fatty acids provides neuroprotection and enhances endogenous neurogenesis after stroke. Curr Mol Med, 13: 1465-1473.
Wang J, Shi Y, Zhang L, Zhang F, Hu X, Zhang W, et al. (2014). Omega-3 polyunsaturated fatty acids enhance cerebral angiogenesis and provide long-term protection after stroke. Neurobiol Dis, 68: 91-103.
Zhang W, Hu X, Yang W, Gao Y, Chen J (2010). Omega-3 polyunsaturated fatty acid supplementation confers long-term neuroprotection against neonatal hypoxic-ischemic brain injury through anti-inflammatory actions. Stroke, 41: 2341-2347.
Fisher M, Feuerstein G, Howells DW, Hurn PD, Kent TA, Savitz SI, et al. (2009). Update of the stroke therapy academic industry roundtable preclinical recommendations. Stroke, 40: 2244-2250.
Pu H, Jiang X, Hu X, Xia J, Hong D, Zhang W, et al. (2016). Delayed Docosahexaenoic Acid Treatment Combined with Dietary Supplementation of Omega-3 Fatty Acids Promotes Long-Term Neurovascular Restoration After Ischemic Stroke. Transl Stroke Res, 7: 521-534.
Wang RY, Wang PS, Yang YR (2003). Effect of age in rats following middle cerebral artery occlusion. Gerontology, 49: 27-32.
Ohab JJ, Fleming S, Blesch A, Carmichael ST (2006). A neurovascular niche for neurogenesis after stroke. J Neurosci, 26: 13007-13016.
Zhang R, Zhang Z, Chopp M (2016). Function of neural stem cells in ischemic brain repair processes. J Cereb Blood Flow Metab, 36: 2034-2043.
Xiong XY, Liu L, Yang QW (2016). Functions and mechanisms of microglia/macrophages in neuroinflammation and neurogenesis after stroke. Prog Neurobiol, 142: 23-44.
Wang Y, Liu G, Hong D, Chen F, Ji X, Cao G (2016). White matter injury in ischemic stroke. Prog Neurobiol, 141: 45-60.
Fern R (2015). Ischemic tolerance in pre-myelinated white matter: the role of astrocyte glycogen in brain pathology. J Cereb Blood Flow Metab, 35: 951-958.
Jalal FY, Yang Y, Thompson JF, Roitbak T, Rosenberg GA (2015). Hypoxia-induced neuroinflammatory white-matter injury reduced by minocycline in SHR/SP. J Cereb Blood Flow Metab, 35: 1145-1153.
Pantoni L (2002). Pathophysiology of age-related cerebral white matter changes. Cerebrovasc Dis, 13 Suppl 2: 7-10.
Chen A, Akinyemi RO, Hase Y, Firbank MJ, Ndung’u MN, Foster V, et al. (2016). Frontal white matter hyperintensities, clasmatodendrosis and gliovascular abnormalities in ageing and post-stroke dementia. Brain, 139: 242-258.
Starr R, Attema B, DeVries GH, Monteiro MJ (1996). Neurofilament phosphorylation is modulated by myelination. J Neurosci Res, 44: 328-337.
Sternberger LA, Sternberger NH (1983). Monoclonal antibodies distinguish phosphorylated and nonphosphorylated forms of neurofilaments in situ. Proc Natl Acad Sci U S A, 80: 6126-6130.
Sun GY, Simonyi A, Fritsche KL, Chuang DY, Hannink M, Gu Z, et al. (2017). Docosahexaenoic acid (DHA): An essential nutrient and a nutraceutical for brain health and diseases. Prostaglandins Leukot Essent Fatty Acids.
Suda S, Katsumata T, Okubo S, Kanamaru T, Suzuki K, Watanabe Y, et al. (2013). Low serum n-3 polyunsaturated fatty acid/n-6 polyunsaturated fatty acid ratio predicts neurological deterioration in Japanese patients with acute ischemic stroke. Cerebrovasc Dis, 36: 388-393.
Lardenoije R, Iatrou A, Kenis G, Kompotis K, Steinbusch HW, Mastroeni D, et al. (2015). The epigenetics of aging and neurodegeneration. Prog Neurobiol, 131: 21-64.
Youyou A, Durand G, Pascal G, Piciotti M, Dumont O, Bourre JM (1986). Recovery of altered fatty acid composition induced by a diet devoid of n-3 fatty acids in myelin, synaptosomes, mitochondria, and microsomes of developing rat brain. J Neurochem, 46: 224-228.
Bourre JM, Pascal G, Durand G, Masson M, Dumont O, Piciotti M (1984). Alterations in the fatty acid composition of rat brain cells (neurons, astrocytes, and oligodendrocytes) and of subcellular fractions (myelin and synaptosomes) induced by a diet devoid of n-3 fatty acids. J Neurochem, 43: 342-348.
Bejot Y, Rouaud O, Jacquin A, Osseby GV, Durier J, Manckoundia P, et al. (2010). Stroke in the very old: incidence, risk factors, clinical features, outcomes and access to resources--a 22-year population-based study. Cerebrovasc Dis, 29: 111-121.
Marini C, Triggiani L, Cimini N, Ciancarelli I, De Santis F, Russo T, et al. (2001). Proportion of older people in the community as a predictor of increasing stroke incidence. Neuroepidemiology, 20: 91-95.
Liang AC, Mandeville ET, Maki T, Shindo A, Som AT, Egawa N, et al. (2016). Effects of Aging on Neural Stem/Progenitor Cells and Oligodendrocyte Precursor Cells After Focal Cerebral Ischemia in Spontaneously Hypertensive Rats. Cell Transplant, 25: 705-714.
Thored P, Wood J, Arvidsson A, Cammenga J, Kokaia Z, Lindvall O (2007). Long-term neuroblast migration along blood vessels in an area with transient angiogenesis and increased vascularization after stroke. Stroke, 38: 3032-3039.
Slevin M, Kumar P, Gaffney J, Kumar S, Krupinski J (2006). Can angiogenesis be exploited to improve stroke outcome? Mechanisms and therapeutic potential. Clin Sci (Lond), 111: 171-183.
dela Pena IC, Yoo A, Tajiri N, Acosta SA, Ji X, Kaneko Y, et al. (2015). Granulocyte colony-stimulating factor attenuates delayed tPA-induced hemorrhagic transformation in ischemic stroke rats by enhancing angiogenesis and vasculogenesis. J Cereb Blood Flow Metab, 35: 338-346.
Zhang RL, Chopp M, Roberts C, Liu X, Wei M, Nejad-Davarani SP, et al. (2014). Stroke increases neural stem cells and angiogenesis in the neurogenic niche of the adult mouse. PLoS One, 9: e113972.
Krupinski J, Kaluza J, Kumar P, Kumar S, Wang JM (1994). Role of angiogenesis in patients with cerebral ischemic stroke. Stroke, 25: 1794-1798.
Tang Y, Wang L, Wang J, Lin X, Wang Y, Jin K, et al. (2016). Ischemia-induced Angiogenesis is Attenuated in Aged Rats. Aging Dis, 7: 326-335.
del Zoppo GJ, Mabuchi T (2003). Cerebral microvessel responses to focal ischemia. J Cereb Blood Flow Metab, 23: 879-894.
Vallon M, Chang J, Zhang H, Kuo CJ (2014). Developmental and pathological angiogenesis in the central nervous system. Cell Mol Life Sci, 71: 3489-3506.
Chopp M, Zhang ZG, Jiang Q (2007). Neurogenesis, angiogenesis, and MRI indices of functional recovery from stroke. Stroke, 38: 827-831.
Ruan L, Wang B, ZhuGe Q, Jin K (2015). Coupling of neurogenesis and angiogenesis after ischemic stroke. Brain Res, 1623: 166-173.
Ihunwo AO, Tembo LH, Dzamalala C (2016). The dynamics of adult neurogenesis in human hippocampus. Neural Regen Res, 11: 1869-1883.
Gould E, Tanapat P, McEwen BS, Flugge G, Fuchs E (1998). Proliferation of granule cell precursors in the dentate gyrus of adult monkeys is diminished by stress. Proc Natl Acad Sci U S A, 95: 3168-3171.
Salazar-Colocho P, Lanciego JL, Del Rio J, Frechilla D (2008). Ischemia induces cell proliferation and neurogenesis in the gerbil hippocampus in response to neuronal death. Neurosci Res, 61: 27-37.
Lichtenwalner RJ, Parent JM (2006). Adult neurogenesis and the ischemic forebrain. J Cereb Blood Flow Metab, 26: 1-20.
Yagita Y, Kitagawa K, Ohtsuki T, Takasawa K, Miyata T, Okano H, et al. (2001). Neurogenesis by progenitor cells in the ischemic adult rat hippocampus. Stroke, 32: 1890-1896.
Badan I, Platt D, Kessler C, Popa-Wagner A (2003). Temporal dynamics of degenerative and regenerative events associated with cerebral ischemia in aged rats. Gerontology, 49: 356-365.
Moraga A, Pradillo JM, Garcia-Culebras A, Palma-Tortosa S, Ballesteros I, Hernandez-Jimenez M, et al. (2015). Aging increases microglial proliferation, delays cell migration, and decreases cortical neurogenesis after focal cerebral ischemia. J Neuroinflammation, 12: 87.
Schaefer MB, Schaefer CA, Schifferings S, Kuhlmann CR, Urban A, Benscheid U, et al. (2016). N-3 vs. n-6 fatty acids differentially influence calcium signalling and adhesion of inflammatory activated monocytes: impact of lipid rafts. Inflamm Res, 65: 881-894.
Valentine RC, Valentine DL (2004). Omega-3 fatty acids in cellular membranes: a unified concept. Prog Lipid Res, 43: 383-402.
He C, Qu X, Cui L, Wang J, Kang JX (2009). Improved spatial learning performance of fat-1 mice is associated with enhanced neurogenesis and neuritogenesis by docosahexaenoic acid. Proc Natl Acad Sci U S A, 106: 11370-11375.
Ali M, Heyob K, Rogers LK (2016). DHA Suppresses Primary Macrophage Inflammatory Responses via Notch 1/ Jagged 1 Signaling. Sci Rep, 6: 22276.
Cameron HA, McKay RD (1999). Restoring production of hippocampal neurons in old age. Nat Neurosci, 2: 894-897.
Dinel AL, Rey C, Bonhomme C, Le Ruyet P, Joffre C, Laye S (2016). Dairy fat blend improves brain DHA and neuroplasticity and regulates corticosterone in mice. Prostaglandins Leukot Essent Fatty Acids, 109: 29-38.
Perez MA, Terreros G, Dagnino-Subiabre A (2013). Long-term omega-3 fatty acid supplementation induces anti-stress effects and improves learning in rats. Behav Brain Funct, 9: 25.
Rivera A, Vanzuli I, Arellano JJ, Butt A (2016). Decreased Regenerative Capacity of Oligodendrocyte Progenitor Cells (NG2-Glia) in the Ageing Brain: A Vicious Cycle of Synaptic Dysfunction, Myelin Loss and Neuronal Disruption? Curr Alzheimer Res, 13: 413-418.
Mallucci G, Peruzzotti-Jametti L, Bernstock JD, Pluchino S (2015). The role of immune cells, glia and neurons in white and gray matter pathology in multiple sclerosis. Prog Neurobiol, 127-128: 1-22.
Jiang X, Pu H, Hu X, Wei Z, Hong D, Zhang W, et al. (2016). A Post-stroke Therapeutic Regimen with Omega-3 Polyunsaturated Fatty Acids that Promotes White Matter Integrity and Beneficial Microglial Responses after Cerebral Ischemia. Transl Stroke Res, 7: 548-561.