Brain size reductions associated with endothelin B receptor mutation, a cause of Hirschsprung's disease

Efficacy and Safety of Sovateltide in Patients with Acute Cerebral Ischaemic Stroke: A Randomised, Double-Blind, Placebo-Controlled, Multicentre, Phase III Clinical Trial

BACKGROUND AND OBJECTIVES

Sovateltide (Tycamzzi™), an endothelin-B (ET-B) receptor agonist, increases cerebral blood flow, has anti-apoptotic activity, and promotes neural repair following cerebral ischaemic stroke. The objectives of this study were to evaluate the efficacy and safety of sovateltide in adult participants with acute cerebral ischaemic stroke.

METHODS

This was a randomised, double-blind, placebo-controlled, multicentre, Phase III clinical trial of sovateltide in participants with cerebral ischaemic stroke receiving standard of care (SOC) in India. Patients aged 18-78 years presenting up to 24 h after the onset of symptoms with radiologic confirmation of ischaemic stroke and a National Institutes of Health Stroke Scale score (NIHSS) of ≥ 6 were enrolled. Patients with recurrent stroke, receiving endovascular therapy, or with intracranial haemorrhage were excluded. The study drug (saline or sovateltide [0.3 µg/kg] was administered intravenously in three doses at 3 ± 1 h intervals on Days 1, 3, and 6, and follow-up was 90 days). The Multivariate Imputation by Chained Equations (MICE) was used to impute the missing assessments on the endpoints. An unpaired t-test, two-way analysis of variance with Tukey's multiple comparison test, and the Chi-square test were used for the statistical analysis. The objective was to determine at Day 90 (1) the number of patients with a modified Rankin Scale score (mRS) 0-2, and (2) the number of patients with an NIHSS 0-5 at 90 days.

RESULTS

Patients were randomised with 80 patients in the sovateltide and 78 in the control group. Patients received the investigational drug at about 18 h of stroke onset in both control and sovateltide groups. The median NIHSS at randomisation was 10.00 (95% CI 9.99-11.65) in the control group and 9.00 (95% CI 9.11-10.46) in the sovateltide group. Seventy patients completed the 90-day follow-up in the control group and 67 in the sovateltide group. The proportion of intention-to-treat (ITT) patients with mRS 0-2 score at Day 90 post-randomisation was 22.67% higher (odds ratio [OR] 2.75, 95% CI 1.37-5.57); similarly, the proportion of patients with NIHSS score of 0-5 at Day 90 was 17.05% more (OR 2.67, 95% CI 1.27-5.90) in the sovateltide group than in the control group. An improvement of ≥ 2 points on the mRS was observed in 51.28% and 72.50% of patients in the control and sovateltide groups, respectively (OR 2.50, 95% CI 1.29-4.81). Seven of 78 patients (8.97%) in the control group and 7 of 80 (8.75%) in the sovateltide group developed intracranial haemorrhage (ICH). The adverse events were not related to sovateltide.

CONCLUSIONS

The sovateltide group had a greater number of cerebral ischaemic stroke patients with lower mRS and NIHSS scores at 90 days post-treatment than the control group. This trial supported the regulatory approval of sovateltide in India, but a multinational RESPECT-ETB trial will be conducted for US approval.

TRIAL REGISTRATION

Clinical Trials Registry, India (CTRI/2019/09/021373) and the United States National Library of Medicine, ClinicalTrials.gov (NCT04047563).

Vascular Contributions to the Neurobiological Effects of Prenatal Alcohol Exposure

Fetal alcohol spectrum disorders (FASD) are often characterized as a cluster of brain-based disabilities. Though cardiovascular effects of prenatal alcohol exposure (PAE) have been documented, the vascular deficits due to PAE are less understood, but may contribute substantially to the severity of neurobehavioral presentation and health outcomes in persons with FASD.

Methods

We conducted a systematic review of research articles curated in PubMed to assess the strength of the research on vascular effects of PAE. 40 pertinent papers were selected, covering studies in both human populations and animal models.

Results

Studies in human populations identified cardiac defects, and defects in vasculature, including increased tortuosity, defects in basement membranes, capillary basal hyperplasia, endarteritis, and disorganized and diminished cerebral vasculature due to PAE. Preclinical studies showed that PAE rapidly and persistently results in vasodilation of large afferent cerebral arteries, but to vasoconstriction of smaller cerebral arteries and microvasculature. Moreover, PAE continues to affect cerebral blood flow into middle-age. Human and animal studies also indicate that ocular vascular parameters may have diagnostic and predictive value. A number of intervening mechanisms were identified, including increased autophagy, inflammation and deficits in mitochondria. Studies in animals identified persistent changes in blood flow and vascular density associated with endocannabinoid, prostacyclin and nitric oxide signaling, as well as calcium mobilization.

Conclusion

Although the brain has been a particular focus of studies on PAE, the cardiovascular system is equally affected. Studies in human populations, though constrained by small sample sizes, did link pathology in major blood vessels and tissue vasculature, including brain vasculature, to PAE. Animal studies highlighted molecular mechanisms that may be useful therapeutic targets. Collectively, these studies suggest that vascular pathology is a possible contributing factor to neurobehavioral and health problems across a lifespan in persons with a diagnosis of FASD. Furthermore, ocular vasculature may serve as a biomarker for neurovascular health in FASD.

Colostomy Delays Cell Loss in the Brain and Improves Juvenile Survival in a Neonatal Rat Model of Hirschsprung's Disease

Hirschsprung's disease is a congenital malformation characterized by the absence of enteric ganglia in the distal intestine and gut obstruction. Our previous study indicates the brain pathology during the disease progression. A subpopulation of Hirschsprung's disease patients is also associated with anomalies of the central nervous system. In the investigation, we studied a rat model of Hirschsprung's disease, known as spotting lethal (sl/sl) ETB-/- rats, which carries a spontaneous deletion in endothelin receptor B (human gene name: EDNRB) and manifests a similar phenotype as humans with Hirschsprung's disease. Homozygous mutant sl/sl rats were successfully rescued from premature death by performing colostomy and dramatically survived to their juvenile age. By the body weight measured, their body growth was not revealed to be significantly different between ETB-/- and wildtype ETB+/+ or heterozygous (+/sl) ETB+/- groups while all underwent the same colostomy. Cell loss was investigated in several brain regions by using terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling assay (TUNEL) in ETB+/+, ETB-/-, and ETB+/- rats. Number of TUNEL-positive cells in the cerebellum and the hippocampus of ETB-/- rats was significantly increased compared with that of the ETB+/+ and ETB+/- rats. TUNEL-positive cells were observed in the molecular layer and granular cell layers of the cerebellum. In contrast, no significant difference in the density of TUNEL-positive cells was revealed in the cerebral cortex. These results suggest that either endothelin receptor B sl mutation or colostomy has predominant lasting effects on the cell survival/loss in the cerebellum and hippocampus of adult ETB-/- rats. Our findings provide the information on cellular changes in the brains of patients with Hirschsprung's disease due to congenital EDNRB mutation as well as clinically relevant interventions.