| 1. |
- Ahnstedt, Hilda, et al.
(författare)
-
U0126 attenuates cerebral vasoconstriction and improves long-term neurologic outcome after stroke in female rats.
- 2015
-
Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 1559-7016 .- 0271-678X. ; 35:3, s. 454-460
-
Tidskriftsartikel (refereegranskat)abstract
- Sex differences are well known in cerebral ischemia and may impact the effect of stroke treatments. In male rats, the MEK1/2 inhibitor U0126 reduces ischemia-induced endothelin type B (ETB) receptor upregulation, infarct size and improves acute neurologic function after experimental stroke. However, responses to this treatment in females and long-term effects on outcome are not known. Initial experiments used in vitro organ culture of cerebral arteries, confirming ERK1/2 activation and increased ETB receptor-mediated vasoconstriction in female cerebral arteries. Transient middle cerebral artery occlusion (tMCAO, 120 minutes) was induced in female Wistar rats, with U0126 (30 mg/kg intraperitoneally) or vehicle administered at 0 and 24 hours of reperfusion, or with no treatment. Infarct volumes were determined and neurologic function was assessed by 6-point and 28-point neuroscores. ETB receptor-mediated contraction was studied with myograph and protein expression with immunohistochemistry. In vitro organ culture and tMCAO resulted in vascular ETB receptor upregulation and activation of ERK1/2 that was prevented by U0126. Although no effect on infarct size, U0126 improved the long-term neurologic function after experimental stroke in female rats. In conclusion, early prevention of the ERK1/2 activation and ETB receptor-mediated vasoconstriction in the cerebral vasculature after ischemic stroke in female rats improves the long-term neurologic outcome.Journal of Cerebral Blood Flow & Metabolism advance online publication, 10 December 2014; doi:10.1038/jcbfm.2014.217.
|
|
| 2. |
- Grell, Anne Sofie, et al.
(författare)
-
Cerebrovascular Gene Expression in Spontaneously Hypertensive Rats After Transient Middle Cerebral Artery Occlusion
- 2017
-
Ingår i: Neuroscience. - : Elsevier BV. - 0306-4522. ; 367, s. 219-232
-
Tidskriftsartikel (refereegranskat)abstract
- Hypertension is a major risk factor for stroke, which is one of the leading global causes of death. In the search for new and effective therapeutic targets in stroke research, we need to understand the influence of hypertension in the vasculature following stroke. We used Affymetrix whole-transcriptome expression profiling as a tool to address gene expression differences between the occluded and non-occluded middle cerebral arteries (MCAs) from spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto (WKY) rats after transient middle cerebral artery occlusion (tMCAO), to provide clues about the pathological mechanisms set in play after stroke. Verified by quantitative PCR, expression of Ccl2, Edn1, Tgfβ2, Olr1 and Serpine1 was significantly increased in the occluded compared to non-occluded MCAs from both SHRs and WKY rats. Additionally, expression of Mmp9, Icam1, Hif1α and Timp1 was increased in the occluded compared to non-occluded MCAs isolated from WKY rats. In comparison between occluded MCAs from SHRs versus occluded MCAs from WKY rats, expression of Ccl2, Olr1 and Serpine1 was significantly increased in SHR MCAs. However, the opposite was observed regarding expression of Edn1. Thus these data suggest that Ccl2, Edn1, Tgfβ2, Olr1 and Serpine1 may be possible mediators of the vascular changes in the occluded MCAs from both SHRs and WKY rats after tMCAO. The aforementioned genes possess biological functions that are consistent with early stroke injuries. In conclusion, these genes may be potential targets in future strategies for acute stroke treatments that can be used in patients with and without hypertension.
|
|
| 3. |
- Grell, Anne Sofie, et al.
(författare)
-
Contractile Responses in Spontaneously Hypertensive Rats after Transient Middle Cerebral Artery Occlusion
- 2018
-
Ingår i: Pharmacology. - : S. Karger AG. - 0031-7012 .- 1423-0313. ; 101, s. 120-132
-
Tidskriftsartikel (refereegranskat)abstract
- Stroke is one of the leading causes of mortality and morbidity worldwide, and few therapeutic treatments have shown beneficial effect clinically. One reason for this could be the lack of risk factors incorporated into the preclinical stroke research. We have previously demonstrated phenotypic receptor changes to be one of the injurious mechanisms occurring after stroke but mostly in healthy rats. The aim of this study was to investigate if hypertension has an effect on vasoconstrictive receptor responses to endothelin 1, sarafotoxin 6c and angiotensin II after stroke by inducing transient middle cerebral artery occlusion in spontaneously hypertensive rats and Wistar-Kyoto rats using the wire-myograph. We demonstrated an increased contractile response to endothelin 1 and extracellular potassium as well as an increased carbachol-induced dilator response in the middle cerebral arteries from hypertensive rats after stroke. This study demonstrates the importance of including risk factors in experimental stroke research.
|
|
| 4. |
- Mostajeran, Maryam
(författare)
-
A Path for Improving Stroke Recovery. Effects of MEK-ERK1/2 Inhibition
- 2018
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present thesis aimed to shed more light on the notion of acute inhibition of extracellular-signal regulated kinase (ERK)1/2 pathway as a treatment to improve stroke recovery. Stroke is a major cause of death and long-term disability worldwide, classified as ischemic or hemorrhagic. In ischemic stroke, interruption of blood flow and deprivation of oxygen and glucose activate death signalling pathways within the area directly affected by ischemia so called “core”. In the region adjacent to core, peri-infarct, cells are hypoperfused, functionally inactive and prone to death if therapeutic strategies do not rescue them. Treatments for ischemic stroke are limited to thrombolysis or thrombectomy. Due to narrow time window and risk of hemorrhagic transformation, few percentages of stroke patients are eligible to receive these treatments. Another approach in stroke therapy is to rescue neurons within peri-infarct region. Despite promising effects of neuroprotective agents in experimental stroke, this approach has failed in clinical trials.Although the ERK1/2 pathway is involved in recovery processes during later stage of stroke, it is a critical modulator of destructive mechanisms i.e. upregulation of cerebrovascular receptors during acute phase. Our previous studies showed that early inhibition of the ERK1/2 pathway reduced ischemic damage and improved functional outcome after experimental stroke. These findings are the base of the present thesis. Although promising, the beneficial effects were only observed during acute phase in male rats. Our hypothesis is that acute inhibition of ERK1/2 pathway will continue to show benefit beyond the acute phase and not negatively interfere with later recovery processes. Further, the present thesis addresses important aspects that should be considered when developing a new treatment such as sex and clinical relevant time point. Thus, this thesis addressed acute blockade of ERK1/2 pathway with regards to important aspects when developing a new treatment. The important aspects evaluated in the present thesis are as follow: (i) Beneficial outcome beyond acute phase and related recovery mechanisms, (ii) A time-window relevant to the clinic, (iii) Acute detrimental mechanisms and effect of U0126 in female rats and (iv) repair-related molecular changes during recovery phase of stroke in female rats. The experimental setup of the thesis was based on an ischemic model on rat. Inhibition of the pathway was achieved by U0126, a inhibitor of mitogen activated protein kinase kinase (MEK)1/2 which is immediately upstream of ERK1/2. In summary, the results of the present thesis showed that acute inhibition of MEKERK1/ 2 pathway is a promising potential treatment for stroke. It has been applicable in a clinically relevant time-window and beneficial for both sexes with persistence of improved functional outcome beyond acute phase. In addition, repair-related molecular changes and activation of ERK1/2 during recovery phase in female rats further supported the idea that ERK1/2 pathway contributes to recovery processes in later stage of stroke. Thus, a path well-investigated may actually lead to better stroke recovery and a future stroke treatment.
|
|
| 5. |
- Mostajeran, Maryam, et al.
(författare)
-
Inhibition of mitogen-activated protein kinase 1/2 in the acute phase of stroke improves long-term neurological outcome and promotes recovery processes in rats.
- 2015
-
Ingår i: Acta Physiologica. - : Wiley. - 1748-1716 .- 1748-1708.
-
Tidskriftsartikel (refereegranskat)abstract
- Extracellular signal-regulated kinase (ERK) 1/2 is activated during acute phase of stroke and contributes to stroke pathology. We have found that acute treatment with MEK1/2 inhibitors decrease infarct size and neurological deficits two days after experimental stroke. However it is not known whether benefits of this inhibition persist long-term. Therefore, the aim of this study was to assess neurological function, infarct size and recovery processes 14 days after stroke in male rats to determine long-term outcome following acute treatment with the MEK1/2 inhibitor U0126.
|
|
| 6. |
- Mostajeran, Maryam, et al.
(författare)
-
Repair-related molecular changes during recovery phase of ischemic stroke in female rats
- 2022
-
Ingår i: BMC Neuroscience. - : Springer Science and Business Media LLC. - 1471-2202. ; 23:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Some degree of spontaneous recovery is usually observed after stroke. Experimental studies have provided information about molecular mechanisms underlying this recovery. However, the majority of pre-clinical stroke studies are performed in male rodents, and females are not well studied. This is a clear discrepancy when considering the clinical situation. Thus, it is important to include females in the evaluation of recovery mechanisms for future therapeutic strategies. This study aimed to evaluate spontaneous recovery and molecular mechanisms involved in the recovery phase two weeks after stroke in female rats. Methods: Transient middle cerebral artery occlusion was induced in female Wistar rats using a filament model. Neurological functions were assessed up to day 14 after stroke. Protein expression of interleukin 10 (IL-10), transforming growth factor (TGF)-β, neuronal specific nuclei protein (NeuN), nestin, tyrosine-protein kinase receptor Tie-2, extracellular signal-regulated kinase (ERK) 1/2, and Akt were evaluated in the peri-infarct and ischemic core compared to contralateral side of the brain at day 14 by western blot. Expression of TGF-β in middle cerebral arteries was evaluated by immunohistochemistry. Results: Spontaneous recovery after stroke was observed from day 2 to day 14 and was accompanied by a significantly higher expression of nestin, p-Akt, p-ERK1/2 and TGF-β in ischemic regions compared to contralateral side at day 14. In addition, a significantly higher expression of TGF-β was observed in occluded versus non-occluded middle cerebral arteries. The expression of Tie-2 and IL-10 did not differ between the ischemic and contralateral sides. Conclusion: Spontaneous recovery after ischemic stroke in female rats was coincided by a difference observed in the expression of molecular markers. The alteration of these markers might be of importance to address future therapeutic strategies.
|
|
| 7. |
- Singh, Birendra, et al.
(författare)
-
Assays for Studying the Role of Vitronectin in Bacterial Adhesion and Serum Resistance
- 2018
-
Ingår i: Journal of Visualized Experiments. - Cambride, USA : Journal of Visualized Experiments. - 1940-087X. ; :140
-
Tidskriftsartikel (refereegranskat)abstract
- Bacteria utilize complement regulators as a means of evading the host immune response. Here, we describe protocols for evaluating the role vitronectin acquisition at the bacterial cell surface plays in resistance to the host immune system. Flow cytometry experiments identified human plasma vitronectin as a ligand for the bacterial receptor outer membrane protein H of Haemophilus influenzae type f. An enzyme-linked immunosorbent assay was employed to characterize the protein-protein interactions between purified recombinant protein H and vitronectin, and binding affinity was assessed using bio-layer interferometry. The biological importance of the binding of vitronectin to protein H at the bacterial cell surface in evasion of the host immune response was confirmed using a serum resistance assay with normal and vitronectin-depleted human serum. The importance of vitronectin in bacterial adherence was analyzed using glass slides with and without vitronectin coating, followed by Gram staining. Finally, bacterial adhesion to human alveolar epithelial cell monolayers was investigated. The protocols described here can be easily adapted to the study of any bacterial species of interest.
|
|
