Reversal of the Detrimental Effects of Post-Stroke Social Isolation by Pair-Housing is Mediated by Activation of BDNF-MAPK/ERK in Aged Mice

Background: Age is an important non-modifiable risk factor for stroke. Stroke rates double every decade after age 55. Social isolation (SI) exacerbates behavioural deficits, slows functional recovery and worsens histological injury after stroke in young animals, primarily by increasing the inflammatory response. However, the inflammatory response differs in aging, and whether the detrimental effects of SI are seen in aged animals is unknown. We hypothesize that acute and chronic post stroke SI will worsen stroke pathology and recovery in aged mice and pair housing (PH) will reverse these effects. Methods: Eighteen-month-old male C57BL/6 mice were pair housed (PH) for two weeks prior to stroke and randomly assigned to various housing conditions immediately after stroke. Behavioral analysis was done weekly starting at day 7. Mice were sacrificed either at 72 hours or 4 weeks after 60-minute right MCAO or sham surgery (n=9-10/group). Results: Mice isolated after stroke (ST-ISO) mice had significantly greater hemispheric infarct volume and neurological deficit scores (p<.05. n=13/group) than pair-housed (PH) stroke mice at 72 hours. SI mice that were isolated immediately after stroke showed significantly higher plasma IL-6 levels compared to PH sham (P<.001, n=13/group ) or PH stroke mice (P<.05) after 72 hour, but levels were similar by 4 weeks post-stroke (n=9-14/group). No change in tissue atrophy was seen after 4 weeks, however a significant interaction [F (1, 28) = 259.6, P<0.001] between housing and stroke was found in the Novel Object Recognition Task (NORT) at day 14. PH led to increased expression of Brain-derived neurotrophic factor (BDNF) and myelin basic protein (MBP) by IHC and western blot (n=5/group for IHC and n= 4/ western blot). Conclusions: Social isolation immediately after stroke led to enhanced injury acutely. Despite similar infarcts at 4 weeks, SI mice had delayed behavioral recovery. Pair housing led to increased expression of BDNF and myelin protein expression. Therefore, the beneficial effects of pair housing may be related to BDNF and MBP expression and enhanced recovery after injury in aged animals.

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Post-Stroke Social Isolation Reduces Cell Proliferation in the Dentate Gyrus and Alters miRNA Profiles in the Aged Female Mice Brain

International Journal of Molecular Sciences ◽

10.3390/ijms22010099 ◽

2020 ◽

Vol 22 (1) ◽

pp. 99

Author(s):

Aleah Holmes ◽

Yan Xu ◽

Juneyoung Lee ◽

Michael E. Maniskas ◽

Liang Zhu ◽

...

Keyword(s):

Cell Proliferation ◽

Dentate Gyrus ◽

Social Isolation ◽

Census Data ◽

Elderly Women ◽

Stroke Recovery ◽

Tissue Loss ◽

Female Mice ◽

Post Stroke ◽

The Brain

Social isolation and loneliness are risk factors for stroke. Elderly women are more likely to be isolated. Census data shows that in homeowners over the age of 65, women are much more likely to live alone. However, the underlying mechanisms of the detrimental effects of isolation have not been well studied in older females. In this study, we hypothesized that isolation impairs post-stroke recovery in aged female mice, leading to dysregulated microRNAs (miRNAs) in the brain, including those previously shown to be involved in response to social isolation (SI). Aged C57BL/6 female mice were subjected to a 60-min middle cerebral artery occlusion and were randomly assigned to either single housing (SI) or continued pair housing (PH) immediately after stroke for 15 days. SI immediately after stroke led to significantly more brain tissue loss after stroke and higher mortality. Furthermore, SI significantly delayed motor and sensory recovery and worsened cognitive function, compared to PH. A decrease in cell proliferation was seen in the dentate gyrus of SI mice assessed by bromodeoxyuridine (BrdU) labeling. miRNAome data analysis revealed changes in several miRNAs in the brain, such as miR-297a-3p and miR-200c-3p, which are known to regulate pathways involved in cell proliferation. In conclusion, our data suggest that SI can lead to a poor post-stroke recovery in aged females and dysregulation of miRNAs and reduced hippocampal cell proliferation.

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Abstract P757: Social Isolation After Stroke Reduces Cell Proliferation and Alters Brain MiRNA Profiles in the Aged Female Mice

Stroke ◽

10.1161/str.52.suppl_1.p757 ◽

2021 ◽

Vol 52 (Suppl_1) ◽

Author(s):

Aleah Holmes ◽

Yan Xu ◽

Juneyoung Lee ◽

Liang Zhu ◽

Venugopal Reddy Venna ◽

...

Keyword(s):

Cell Proliferation ◽

Social Isolation ◽

Elderly Women ◽

Epidemiological Studies ◽

Stroke Recovery ◽

Tissue Loss ◽

Adhesive Tape ◽

Female Mice ◽

Post Stroke ◽

Hippocampal Cell

Background: Social isolation (SI) and loneliness are risk factors for stroke. Epidemiological studies have shown that women tend to have a higher risk of stroke at later age and elderly women are more likely to be isolated. The mechanisms underlying the detrimental effects of SI have not been well studied in older females. We hypothesized that SI in aged female mice would lead to impaired post-stroke recovery and could lead to differential regulation of microRNAs (miRNAs). Methods: In this study, aged C57BL/6N female mice were subjected to a 60-minute middle cerebral artery occlusion (MCAO) and were randomly assigned to either single housing (SI) or continued pair housing (PH) immediately after stroke for 15 days. Infarct size, mortality and recovery was assessed using open field, the adhesive-tape removal task and the Y-maze test. MiRNAs were comprehensively analyzed by miRNAome analysis on stroke brain, and changes in hippocampal cell proliferation was assessed from perfused brain sections. Results: Importantly, SI immediately after stroke led to significantly larger tissue loss and higher mortality in aged females, it also significantly delayed motor/sensory recovery in the adhesive removal test and impaired overall locomotor activity. In addition, these mice also demonstrated worse post-stroke cognitive function. In parallel, brains of these mice showed reduced miR-297a-3p expression and increased miR-18a-3p and miR-200c-3p expression with SI compared to PH cohort and reduced hippocampal cell proliferation. Conclusion: The results from this study suggest that SI after stroke can increase mortality and significantly impair post-stroke recovery in aged female mice. These worse outcomes are in parallel to the significant changes in several miRNAs and reduced hippocampal cell proliferation.

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Inhibition of miR-141-3p Ameliorates the Negative Effects of Poststroke Social Isolation in Aged Mice

Stroke ◽

10.1161/strokeaha.118.020627 ◽

2018 ◽

Vol 49 (7) ◽

pp. 1701-1707 ◽

Cited By ~ 13

Author(s):

Rajkumar Verma ◽

Rodney M. Ritzel ◽

Nia M. Harris ◽

Juneyoung Lee ◽

TaeHee Kim ◽

...

Keyword(s):

Social Isolation ◽

Negative Effects ◽

Aged Mice

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Abstract TP78: Combination of Neuroprotective Drug and Neural Stem Cells Benefits Aged Stroke Mice with Delayed Tissue Plasminogen Activator Treatment

Stroke ◽

10.1161/str.48.suppl_1.tp78 ◽

2017 ◽

Vol 48 (suppl_1) ◽

Author(s):

Auston Eckert ◽

Milton H Hamblin ◽

Jean-Pyo Lee

Keyword(s):

Stem Cells ◽

Young Adult ◽

Neural Stem Cells ◽

Plasminogen Activator ◽

Tissue Plasminogen Activator ◽

Inflammatory Drug ◽

Aged Mice ◽

Post Stroke ◽

Adult Mice ◽

Tissue Plasminogen

Background: Presently, tissue plasminogen activator (tPA) is the sole FDA-approved antithrombotic treatment available for stroke. However, tPA’s harmful side effects within the central nervous system can exacerbate blood-brain barrier (BBB) damage and increase mortality. Patients should receive tPA less than 4.5 hours post-stroke. Although age alone is not an impediment for tPA treatment, the harmful effects of delayed tPA (>4.5h), particularly on aged stroke animals, have not been well studied. We reported that intracranial transplantation of neural stem cells (hNSCs) ameliorates BBB damage caused by ischemic stroke. In this study, we examined the combined effects of minocycline (a neuroprotective and anti-inflammatory drug) and hNSC transplantation on the mortality of delayed tPA-treated aged mice within 48h post-stroke. Methods and Results: We utilized the middle cerebral artery occlusion stroke mouse model to induce focal cerebral ischemia followed by reperfusion (MCAO/R). 6h post-MCAO, we administered tPA intravenously. Minocycline was administered intraperitoneally at various time points prior to tPA injection. One day post-stroke, we injected hNSCs intracranially. Previously, we reported that hNSCs (both human and mouse) transplanted into the brain 24h post-stroke rapidly improve neurological outcome in young-adult mice (4-5mo). In our current study, tPA administered within 4.5h did not increase mortality in either young-adult or aged mice. However, we found delayed tPA treatment (6h post-stroke) significantly increased the mortality of aged mice (13-18 mo) but not in young-adult mice. Here, we report that by combining minocycline prior to tPA significantly reduced mortality. Furthermore, transplanting hNSCs in minocycline-treated mice further ameliorated the pathophysiology caused by delayed tPA. Conclusions: Our findings implicate that administering the anti-apototic and anti-inflammatory drug prior to tPA injection, and then post-treating with multipotent neuroprotective hNSCs might expand the time window of tPA and reduce reperfusion injury.

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Abstract 181: Stroke Induces a Differential Colonic Epithelial Response and Leads to Impaired Gut Integrity and Increased Post-Stroke Infections in Aged Mice

Stroke ◽

10.1161/str.49.suppl_1.181 ◽

2018 ◽

Vol 49 (Suppl_1) ◽

Author(s):

Juneyoung Lee ◽

Monica Spychala ◽

John d’Aigle ◽

Victoria Quaicoe ◽

Louise D McCullough ◽

...

Keyword(s):

Aged Mice ◽

Post Stroke

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Social isolation and outcomes post stroke

Neurology ◽

10.1212/01.wnl.0000163510.79351.af ◽

2005 ◽

Vol 64 (11) ◽

pp. 1888-1892 ◽

Cited By ~ 169

Author(s):

B. Boden-Albala ◽

E. Litwak ◽

M.S.V. Elkind ◽

T. Rundek ◽

R. L. Sacco

Keyword(s):

Social Isolation ◽

Post Stroke

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Effects of Long-term Social Isolation on Central, Behavioural and Metabolic Parameters in Middle-Aged Mice

Behavioural Brain Research ◽

10.1016/j.bbr.2021.113630 ◽

2021 ◽

pp. 113630

Author(s):

Izabelle Dias Benfato ◽

Ana Carolina Silvares Quintanilha ◽

Jessica Salles Henrique ◽

Melyssa Alves Souza ◽

Barbara dos Anjos Rosário ◽

...

Keyword(s):

Social Isolation ◽

Metabolic Parameters ◽

Middle Aged ◽

Aged Mice

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Age-dependent involvement of gut mast cells and histamine in post-stroke inflammation

10.21203/rs.2.21718/v1 ◽

2020 ◽

Author(s):

Maria Pilar Blasco ◽

Anjali Chauhan ◽

Pedram Honarpisheh ◽

Hilda Ahnstedt ◽

John d’Aigle ◽

...

Keyword(s):

Ischemic Stroke ◽

Mast Cells ◽

Receptor Expression ◽

Mast Cell Activation ◽

Low Grade ◽

Gut Inflammation ◽

Aged Mice ◽

Post Stroke ◽

Age Related ◽

The Brain

Abstract Background Risk of stroke-related morbidity and mortality increases significantly with age. Aging is associated with chronic, low-grade inflammation, which is thought to contribute to the poorer outcomes after stroke seen in the elderly. Histamine (HA) is a major molecular mediator of inflammation and mast cells residing in the gut are a primary source of histamine. Methods Stroke was induced in male C57BL/6J mice at 3 months (young) and 20 months (aged) of age. Role of histamine after stroke was examined using young (Yg) and aged (Ag) mice, mice underwent MCAO surgery and were euthanized at 6h, 24h and 7 days post-ischemia; sham mice received the same surgery but no MCAO. In this work, we evaluated whether worsened outcomes after experimental stroke in aged mice was associated with age-related changes in mast cells, histamine levels, and histamine receptor expression in the gut, brain, and plasma. Results We found increased numbers of mast cells in the gut and the brain with aging. Using the middle cerebral artery occlusion (MCAO) model of ischemic stroke, we demonstrate that stroke leads to increased numbers of mast cells and histamine receptors in the gut. These gut-centric changes are associated with elevated levels of HA and other pro-inflammatory cytokines including IL-6, G-CSF, TNF-α, and IFN-γ in the peripheral circulation. Our data also shows that post-stroke gut inflammation led to a significant reduction of mucin-producing goblet cells and a loss of gut barrier integrity. Lastly, gut inflammation after stroke is associated with changes in the composition of the gut microbiota as early as 24 hours post-stroke. Conclusion An important theme emerging from our results is that acute inflammatory events following ischemic insults in the brain persist longer in the aged mice when compared to younger animals. Taken together, our findings implicate mast cell activation and histamine signaling as a part of peripheral inflammatory response after ischemic stroke, which are profound in aged animals. Interfering with histamine signaling orally might provide translational value to improve stroke outcome.

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Abstract WMP74: Sex Differences in T Cell Immune Responses and Outcome After Stroke in Aged Mice

Stroke ◽

10.1161/str.48.suppl_1.wmp74 ◽

2017 ◽

Vol 48 (suppl_1) ◽

Author(s):

Hilda Ahnstedt ◽

Anthony Patrizz ◽

Javiera Bravo-Alegria ◽

Monica Sphychala ◽

Meaghan Roy-O’Reilly ◽

...

Keyword(s):

Flow Cytometry ◽

T Cells ◽

Sex Differences ◽

Immune Responses ◽

T Regulatory Cells ◽

Hemorrhagic Transformation ◽

Regulatory Cells ◽

Male And Female ◽

Aged Mice ◽

Post Stroke

Introduction: Sex differences are increasingly recognized in stroke. Stroke incidence is higher in men than in women until an advanced age and women have higher mortality and morbidity. Inflammatory responses are key determinants of outcome but have not been well studies in aged animals. Hypothesis: We hypothesize that there are important sex differences in inflammation in aged male and female mice. Results: We quantified T cells and T regulatory cells, as well as functional outcome after stroke in aged mice. Male and female C57BL/6 mice (20-21 months) were subjected to 60 min middle cerebral artery occlusion (n=16) by the filament model, or sham surgery (n=7). Immune responses in brain, blood and spleen were investigated 15 days post-stroke by flow cytometry. Functional outcomes were assessed at day 3, 7 and 14. Mortality was 25% in females and occurred at day 1, while in males 50% mortality was seen between day 3 and 9. Hemorrhagic transformation was seen in 53% of the males that died (5/8) and in none of the females (0/4). Flow cytometry analysis at day 15 showed significantly higher levels of CD8 + T cells in the blood after stroke in males compared to females (73±5% of CD3 + T cells vs 52±3%, P<0.001). CD8 + T cells were found in brains from males and females after stroke but levels were not different from sham (Male Stroke: 64±7%, Female Stroke: 58±5%). Independent of the type of surgery (stroke or sham), we observed higher levels of splenic CD8 + T cells in males (P<0.01). T regulatory cells were significantly increased in the brain after stroke in males compared to sham (P<0.01), but not in females. Open-field testing showed a decrease in center visits after stroke in both sexes at 3 days, however males spent more time immobile (P<0.01) indicating decreased locomotor activity and/or anxiety. This difference equalized at 7 and 14 days post-stroke. Conclusion: Higher mortality and hemorrhagic transformation rates were seen in aged males than in females after stroke. This may be associated with the elevated levels of CD8 + T cells in blood and possible unfavorable effects on blood brain barrier permeability.

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