The Role of Losartan as a Potential Neuroregenerative Pharmacological Agent after Aneurysmal Subarachnoid Haemorrhage

Quantification of the Rupture Potential of Patient-Specific Intracranial Aneurysms under Contact Constraints

Intracranial aneurysms (IAs) are localized enlargements of cerebral blood vessels that cause substantial rates of mortality and morbidity in humans. The rupture possibility of these aneurysms is a critical medical challenge for physicians during treatment planning. This treatment planning while assessing the rupture potential of aneurysms becomes more complicated when they are constrained by an adjacent structure such as optic nerve tissues or bones, which is not widely studied yet. In this work, we considered and studied a constitutive model to investigate the bio-mechanical response of image-based patient-specific IA data using cardiovascular structural mechanics equations. We performed biomechanical modeling and simulations of four different patient-specific aneurysms’ data (three middle cerebral arteries and one internal carotid artery) to assess the rupture potential of those aneurysms under a plane contact constraint. Our results suggest that aneurysms with plane contact constraints produce less or almost similar maximum wall effective stress compared to aneurysms with no contact constraints. In our research findings, we observed that a plane contact constraint on top of an internal carotid artery might work as a protective wall due to the 16.6% reduction in maximum wall effective stress than that for the case where there is no contact on top of the aneurysm.

Levosimendan as a therapeutic strategy to prevent neuroinflammation after aneurysmal subarachnoid hemorrhage?

BACKGROUND

Poor patient outcomes after aneurysmal subarachnoid hemorrhage (SAH) occur due to a multifactorial process, mainly involving cerebral inflammation (CI), delayed cerebral vasospasm (DCVS), and delayed cerebral ischemia, followed by neurodegeneration. CI is mainly triggered by enhanced synthesis of serotonin (5-HT), prostaglandin F2alpha (PGF2a), and cytokines such as interleukins. Levosimendan (LV), a calcium-channel sensitizer, has already displayed anti-inflammatory effects in patients with severe heart failure. Therefore, we wanted to elucidate its potential anti-inflammatory role on the cerebral vasculature after SAH.

METHODS

Experimental SAH was induced by using an experimental double-hemorrhage model. Sprague Dawley rats were harvested on day 3 and day 5 after the ictus. The basilar artery was used for isometric investigations of the muscular media tone. Vessel segments were either preincubated with LV or without, with precontraction performed with 5-HT or PGF2a followed by application of acetylcholine (ACh) or LV.

RESULTS

After preincubation with LV 10^-4 M and 5-HT precontraction, ACh triggered a strong vasorelaxation in sham segments (LV 10^-4 M, E_max 65%; LV 10^-5 M, E_max 48%; no LV, E_max 53%). Interestingly, SAH D3 (LV 10^-4, E_max 76%) and D5 (LV 10^-4, E_max 79%) segments showed greater vasorelaxation compared with sham. An LV series after PGF2a precontraction showed significantly enhanced relaxation in the sham (P=0.004) and SAH groups (P=0.0008) compared with solvent control vessels.

CONCLUSIONS

LV application after SAH seems to beneficially influence DCVS by antagonizing 5-HT- and PGF2a-triggered vasoconstriction. Considering this spasmolytic effect, LV might have a role in the treatment of SAH, additionally in selected patients suffering takotsubo cardiomyopathy.