Implications of Post-recanalization Perfusion Deficit After Acute Ischemic Stroke: a Scoping Review of Clinical and Preclinical Imaging Studies

The goal of reperfusion therapy for acute ischemic stroke (AIS) is to restore cerebral blood flow through recanalization of the occluded vessel. Unfortunately, successful recanalization does not always result in favorable clinical outcome. Post-recanalization perfusion deficits (PRPDs), constituted by cerebral hypo- or hyperperfusion, may contribute to lagging patient recovery rates, but its clinical significance remains unclear. This scoping review provides an overview of clinical and preclinical findings on post-ischemic reperfusion, aiming to elucidate the pattern and consequences of PRPD from a translational perspective. The MEDLINE database was searched for quantitative clinical and preclinical studies of AIS reporting PRPD based on cerebral circulation parameters acquired by translational tomographic imaging methods. PRPD and stroke outcome were mapped on a charting table, creating an overview of PRPD after AIS. Twenty-two clinical and twenty-two preclinical studies were included. Post-recanalization hypoperfusion is rarely reported in clinical studies (4/22) but unequivocally associated with detrimental outcome. Post-recanalization hyperperfusion is more commonly reported (18/22 clinical studies) and may be associated with positive or negative outcome. PRPD has been replicated in animal studies, offering mechanistic insights into causes and consequences of PRPD and allowing delineation of possible courses of PRPD. Complex relationships exist between PRPD and stroke outcome. Diversity in methods and lack of standardized definitions in reperfusion studies complicate the characterization of reperfusion patterns. Recommendations are made to advance the understanding of PRPD mechanisms and to further disentangle the relation between PRPD and disease outcome.

Genetic liability to migraine and functional outcome after ischemic stroke

BACKGROUND AND PURPOSE

To evaluate the association of genetic liability to migraine with functional outcome after ischemic stroke using Mendelian randomization.

METHODS

Genetic proxies for migraine were obtained from the largest genome-wide association study meta-analysis of 102,084 migraine cases and 771,257 controls. Genetic associations with functional outcome after ischemic stroke were obtained from the Genetics of Ischemic Stroke Functional Outcome network study (N = 6021). Poor functional outcome after ischemic stroke was defined as a score of 3-6 on the modified Rankin scale at 3 months (N = 2280). The inverse-variance weighted method was used to estimate the association of genetic liability to migraine with functional outcome, and we performed sensitivity analyses to assess the robustness of results.

RESULTS

Genetic liability to migraine was associated with poor functional outcome after ischemic stroke (odds ratio of poor functional outcome per doubling in migraine odds 1.22, 95% confidence interval 1.02-1.45, p = 0.031). This association remained directionally consistent across sensitivity analyses.

CONCLUSIONS

This study provides genetic support that migraine is associated with poor functional outcome after ischemic stroke. These findings warrant further follow-up and, if replicated, may have clinical implications for post-stroke recovery.

Neurological and psychiatric comorbidities of migraine: Concepts and future perspectives

BACKGROUND

This narrative review aims to discuss several common neurological and psychiatric disorders that show comorbidity with migraine. Not only can we gain pathophysiological insights by studying these disorders, comorbidities also have important implications for treating migraine patients in clinical practice.

METHODS

A literature search on PubMed and Embase was conducted with the keywords "comorbidity", "migraine disorders", "migraine with aura", "migraine without aura", "depression", "depressive disorders", "epilepsy", "stroke", "patent foramen ovale", "sleep wake disorders", "restless legs syndrome", "genetics", "therapeutics".

RESULTS

Several common neurological and psychiatric disorders show comorbidity with migraine. Major depression and migraine show bidirectional causality and have shared genetic factors. Dysregulation of both hypothalamic and thalamic pathways have been implicated as a possibly cause. The increased risk of ischaemic stroke in migraine likely involves spreading depolarizations. Epilepsy is not only bidirectionally related to migraine, but is also co-occurring in monogenic migraine syndromes. Neuronal hyperexcitability is an important overlapping mechanism between these conditions. Hypothalamic dysfunction is suggested as the underlying mechanism for comorbidity between sleep disorders and migraine and might explain altered circadian timing in migraine.

CONCLUSION

These comorbid conditions in migraine with distinct pathophysiological mechanisms have important implications for best treatment choices and may provide clues for future approaches.

OnabotulinumtoxinA in elderly patients with chronic migraine: insights from a real-life European multicenter study

INTRODUCTION

Although migraine prevalence decreases with aging, some older patients still suffer from chronic migraine (CM). This study aimed to investigate the outcome of OnabotulinumtoxinA (OBT-A) as preventative therapy in elderly CM patients.

METHODS

This is a post hoc analysis of real-life prospectively collected data at 16 European headache centers on CM patients treated with OBT-A over the first three treatment cycles (i.e., Cy1-3). We defined: OLD patients aged ≥ 65 years and nonOLD those < 65-year-old. The primary endpoint was the changes in monthly headache days (MHDs) from baseline to Cy 1-3 in OLD compared with nonOLD participants. The secondary endpoints were the responder rate (RR) ≥ 50%, conversion to episodic migraine (EM) and the changes in days with acute medication use (DAMs).

RESULTS

In a cohort of 2831 CM patients, 235 were OLD (8.3%, 73.2% females, 69.6 years SD 4.7). MHDs decreased from baseline (24.8 SD 6.2) to Cy-1 (17.5 SD 9.1, p < 0.000001), from Cy-1 to Cy-2 (14.8 SD 9.2, p < 0.0001), and from Cy-2 to Cy-3 (11.9 SD 7.9, p = 0.001). DAMs progressively reduced from baseline (19.2 SD 9.8) to Cy-1 (11.9 SD 8.8, p < 0.00001), to Cy-2 (10.9 SD 8.6, p = 0.012), to Cy-3 (9.6 SD 7.4, p = 0.049). The 50%RR increased from 30.7% (Cy-1) to 34.5% (Cy-2), to 38.7% (Cy-3). The above outcome measures did not differ in OLD compared with nonOLD patients.

CONCLUSION

In a population of elderly CM patients with a long history of migraine OBT-A provided a significant benefit, over the first three treatment cycles, as good as in non-old patients.

MicroRNA-155 influences cell damage in ischemic stroke via TLR4/MYD88 signaling pathway

Cerebral ischemic stroke (CIS) is extremely harmful, and its treatment should be underpinned by understanding its pathogenic mechanism. This study was designed to determine the involvement of miR-155 in CIS development via the TLR4/MyD88 signaling pathway. First, we quantified serum miR-155 in patients with CIS and healthy individuals, and found high expression of miR-155 in such patients and a decrease in it in the patients after therapy (P < 0.05). Serum miR-155 demonstrated a favorable function in predicting the development and prognosis of CIS (P < 0.001). We also conducted a mouse assay, and found that knocking out miR-155 can improve the neurological function of mice and suppress protein TLR4 and MyD88 (all P < 0.05). Finally, we carried out a cell assay, and found enhancement in the activity of SH-SY5Y cells, decrease in their apoptosis, and protein TLR4 and MyD88 in them after suppression of miR-155 (all P < 0.05). Furthermore, we also found complete reverse by TLR4/MyD88 pathway inhibitor on the influence of increasing miR-155 on cells (P > 0.05). Therefore, with an increase in cases with CIS, miR-155 takes a part in the development of cell damage by activating TLR4/MyD88, and it is probably the key to diagnosing and treating CIS.