Characterising the phenotype and impact of adipose in idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH) is a rare disease that primarily affects obese women of reproductive age, characterised by raised intracranial pressure (ICP) and papilloedema that drives chronic debilitating headache and visual loss. The aetiology of IIH is uncertain, however it is clear that weight loss is therapeutic and reduces ICP, headache, and visual morbidity. Novel data has highlighted that female IIH patients have an androgen excess phenotype. However the role of adipose tissue and androgens in the pathogenesis of IIH remains unclear. Utilising RNA-sequencing, NMR-based metabolomics and secretomic techniques, it has been identified that ex vivo subcutaneous adipose tissue from female IIH patients has features of glucocorticoid excess including increased lipolysis, ribosomal subunit depletion and a preference for lipid synthesis, driven by intra-adipose cortisol accumulation. Moreover, this phenotype is driving hyperleptinaemia in IIH patients. Additionally, a novel in vitro Na+/K+ ATPase activity assay was developed, which demonstrated that testosterone increases Na+/K+ ATPase activity, suggesting capacity to increase ICP. Together, these data highlight that adipose tissue in IIH has characteristics of glucocorticoid excess, contributing to a specific metabolic phenotype and that testosterone could be driving raised intracranial pressure, highlighting routes for the development of novel therapeutics and treatments for IIH

Understanding the link between obesity and headache- with focus on migraine and idiopathic intracranial hypertension

Abstract Background Obesity confers adverse effects to every system in the body including the central nervous system. Obesity is associated with both migraine and idiopathic intracranial hypertension (IIH). The mechanisms underlying the association between obesity and these headache diseases remain unclear. Methods We conducted a narrative review of the evidence in both humans and rodents, for the putative mechanisms underlying the link between obesity, migraine and IIH. Results Truncal adiposity, a key feature of obesity, is associated with increased migraine morbidity and disability through increased headache severity, frequency and more severe cutaneous allodynia. Obesity may also increase intracranial pressure and could contribute to headache morbidity in migraine and be causative in IIH headache. Weight loss can improve both migraine and IIH headache. Preclinical research highlights that obesity increases the sensitivity of the trigeminovascular system to noxious stimuli including inflammatory stimuli, but the underlying molecular mechanisms remain unelucidated. Conclusions This review highlights that at the epidemiological and clinical level, obesity increases morbidity in migraine and IIH headache, where weight loss can improve headache morbidity. However, further research is required to understand the molecular underpinnings of obesity related headache in order to generate novel treatments