The effect of GLP-1RA exenatide on idiopathic intracranial hypertension: a randomized clinical trial

Targeting microglial GLP1R in epilepsy: A novel approach to modulate neuroinflammation and neuronal apoptosis

BACKGROUND

Epilepsy is a prevalent disorder of the central nervous system. Approximately, one-third of patients show resistance to pharmacological interventions. The pathogenesis of epilepsy is complex, and neuronal apoptosis plays a critical role. Aberrantly reactive astrocytes, induced by cytokine release from activated microglia, may lead to neuronal apoptosis. This study investigated the role of glucagon-like peptide 1 receptor (GLP1R) in microglial activation in epilepsy and its impact on astrocyte-mediated neurotoxicity.

METHODS

We used human hippocampal tissue from patients with temporal lobe epilepsy and a pilocarpine-induced epileptic mouse model to assess neurobiological changes in epilepsy. BV2 microglial cells and primary astrocytes were used to evaluate cytokine release and astrocyte activation in vitro. The involvement of GLP1R was explored using the GLP1R agonist, Exendin-4 (Ex-4).

RESULTS

Our findings indicated that reduced GLP1R expression in hippocampal microglia in both epileptic mouse models and human patients, correlated with increased cytokine release and astrocyte activation. Ex-4 treatment restored microglial homeostasis, decreased cytokine secretion, and reduced astrocyte activation, particularly of the A1 phenotype. These changes were associated with a reduction in neuronal apoptosis. In addition, Ex-4 treatment significantly decreased the frequency and duration of seizures in epileptic mice.

CONCLUSIONS

This study highlights the crucial role of microglial GLP1R in epilepsy pathophysiology. GLP1R downregulation contributes to microglial- and astrocyte-mediated neurotoxicity, exacerbating neuronal death and seizures. Activation of GLP1R with Ex-4 has emerged as a promising therapeutic strategy to reduce neuroinflammation, protect neuronal cells, and control seizures in epilepsy. This study provides a foundation for developing novel antiepileptic therapies targeting microglial GLP1R, with the potential to improve outcomes in patients with epilepsy.

GLP-1 programs the neurovascular landscape

Readily available nutrient-rich foods exploit our inherent drive to overconsume, creating an environment of overnutrition. This transformative setting has led to persistent health issues, such as obesity and metabolic syndrome. The development of glucagon-like peptide-1 receptor (GLP-1R) agonists reveals our ability to pharmacologically manage weight and address metabolic conditions. Obesity is directly linked to chronic low-grade inflammation, connecting our metabolic environment to neurodegenerative diseases. GLP-1R agonism in curbing obesity, achieved by impacting appetite and addressing associated metabolic defects, is revealing additional benefits extending beyond weight loss. Whether GLP-1R agonism directly impacts brain health or does so indirectly through improved metabolic health remains to be elucidated. In exploring the intricate connection between obesity and neurological conditions, recent literature suggests that GLP-1R agonism may have the capacity to shape the neurovascular landscape. Thus, GLP-1R agonism emerges as a promising strategy for addressing the complex interplay between metabolic health and cognitive well-being.

Association Between Glucagon-Like Peptide-1 Receptor Agonists Exposure and Intraocular Pressure Change: GLP-1 Receptor Agonists and Intraocular Pressure Change

PURPOSE

This study evaluates the effects of glucagon-like peptide-1 receptor (GLP-1R) agonists on intraocular pressure (IOP).

DESIGN

Retrospective clinical cohort study.

METHODS

The University of California Health Data Warehouse was queried for patients exposed to GLP-1R agonists or other oral antidiabetics. A total of 1247 glaucoma surgery and treatment naïve eyes of 626 patientson GLP-1R agonists and 1083 glaucoma surgery and treatment naïve eyes of 547 patients on other oral antidiabetics were included. Index date was defined as the date of first exposure to the medication. Eyes with at least one pre-exposure and one post-exposure tonometry records within 365 days of the index date were included. Clinical and laboratory data were extracted. Eyes were excluded upon exposure to glaucoma hypotensive medication or glaucoma surgery. The primary outcome measure was ∆IOP after exposure, which was analyzed using a paired t test and generalized estimating equations (GEE) RESULTS: The median age was 66.2 years [IQR = 18.3]; 607 (51.7%) were female, and 667 (56.9%) were Caucasian. Median pre-exposure IOP, hemoglobin A1c, and body mass index were 15.2 mm Hg [IQR = 3.8], 7.5 [IQR = 2.4], and 29.8 [IQR = 9.4], respectively. A total of 776 individuals (66.1%) had diabetes, with the median number of active oral antidiabetics being 1.0 [IQR = 1.0], and 441 (37.5%) being insulin users. Several pre-exposure characteristics differed between the groups. The mean ∆IOP was -0.4 ± 2.8 mm Hg (paired t test P < .001) and -0.2 ± 3.3 mm Hg (paired t test P = .297) in the GLP-1R agonist and other antidiabetics groups, respectively. Pre-exposure IOP was the only independent predictor of ΔIOP in multivariable GEE. Sensitivity analyses yielded similar results.

CONCLUSIONS

Although GLP-1R agonists were significantly associated with a decrease in IOP in the paired analysis, they were not associated with ΔIOP in multivariable GEE. Moreover, the difference in ΔIOP between the two groups was small.

Discovery of potential antidiabetic peptides using deep learning

Antidiabetic peptides (ADPs), peptides with potential antidiabetic activity, hold significant importance in the treatment and control of diabetes. Despite their therapeutic potential, the discovery and prediction of ADPs remain challenging due to limited data, the complex nature of peptide functions, and the expensive and time-consuming nature of traditional wet lab experiments. This study aims to address these challenges by exploring methods for the discovery and prediction of ADPs using advanced deep learning techniques. Specifically, we developed two models: a single-channel CNN and a three-channel neural network (CNN + RNN + Bi-LSTM). ADPs were primarily gathered from the BioDADPep database, alongside thousands of non-ADPs sourced from anticancer, antibacterial, and antiviral peptide datasets. Subsequently, data preprocessing was performed with the evolutionary scale model (ESM-2), followed by model training and evaluation through 10-fold cross-validation. Furthermore, this work collected a series of newly published ADPs as an independent test set through literature review, and found that the CNN model achieved the highest accuracy (90.48 %) in predicting the independent test set, surpassing existing ADP prediction tools. Finally, the application of the model was considered. SeqGAN was used to generate new candidate ADPs, followed by screening with the constructed CNN model. Selected peptides were then evaluated using physicochemical property prediction and structural forecasts for pharmaceutical potential. In summary, this study not only established robust ADP prediction models but also employed these models to screen a batch of potential ADPs, addressing a critical need in the field of peptide-based antidiabetic research.

Comparative Effects of GLP-1 Receptor Agonists and Metformin on Glaucoma Risk in Type 2 Diabetes Patients

PURPOSE

To compare effects of glucagon-like peptide-1 (GLP-1) receptor agonists and metformin on the risk of primary open-angle glaucoma (POAG), ocular hypertension, and the need for first-line glaucoma treatments in patients with type 2 diabetes.

DESIGN

A retrospective cohort study was conducted using electronic medical records (EMR) data from the from an international electronic health record network, covering a period from May 2006 to May 2024.

PARTICIPANTS

Patients diagnosed with type 2 diabetes mellitus (T2DM) who were treated with either GLP-1 receptor agonists or metformin.

METHODS

Data from 120 healthcare organizations across 17 countries were analyzed. Patient outcomes were assessed at 1, 2, and 3 years. Propensity score matching (PSM) was used to balance covariates such as demographics, comorbidities, and medication usage. Risk ratios (RR) with 95% confidence intervals (CI) were calculated.

MAIN OUTCOME MEASURES

Incidence of POAG, ocular hypertension, and the need for first-line treatments including beta-blockers, prostaglandin analogues, brimonidine, brinzolamide, dorzolamide, netarsudil, and laser trabeculoplasty.

RESULTS

After PSM, both groups included 61,998 patients at the 1-year follow-up, 27,414 at the 2-year follow-up, and 14,100 at the 3-year follow-up. Patients treated with GLP-1 receptor agonists had a significantly decreased risk of developing POAG compared to those on metformin at 1 year (RR 0.59, 95% CI 0.39-0.88), 2 years (RR 0.50, 95% CI 0.32-0.78), and 3 years (RR 0.59, 95% CI 0.37-0.94). Similar protective effects were observed for ocular hypertension with risk reductions of 56% at 1 year (RR 0.44, 95% CI 0.31-0.62), 57% at 2 years (RR 0.43, 95% CI 0.30-0.62), and 49% at 3 years (RR 0.51, 95% CI 0.34-0.75). The risk of first-line therapy initiation was also lower in the GLP-1 receptor agonists group at 1 year (RR 0.63, 95% CI 0.53-0.74), 2 years (RR 0.71, 95% CI 0.59-0.85), and 3 years (RR 0.75, 95% CI 0.62-0.91).

CONCLUSIONS

GLP-1 receptor agonists are associated with a significantly lower incidence of POAG, ocular hypertension, and the need for first-line glaucoma treatments compared to metformin in patients with type 2 diabetes. These findings highlight the potential ocular benefits of GLP-1 receptor agonists and their expanding role in the clinical management of diabetic patients.

Symptomatic idiopathic intracranial hypertension triggered by Ramadan intermittent fasting: a case report

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a disorder that primarily affects obese women of reproductive age. The exact pathogenesis of IIH is unknown though multiple etiologies have been proposed.

CASE PRESENTATION

We report a case of IIH triggered by first-time Ramadan intermittent fasting (RIF) in an 18-year-old woman. Our patient developed new onset headaches, diplopia, and pulsatile tinnitus with examination notable for bilateral papilledema and lumbar puncture revealing an elevated opening pressure. Her symptoms resolved after cessation of RIF, apart from persistent left sided tinnitus which later resolved with acetazolamide administration.

CONCLUSION

This case report uniquely illustrates that RIF may provoke symptomatic IIH. We hypothesize that a decreased concentration of glucagon-like peptide-1 (GLP-1) induced by fasting results in decreased GLP-1 receptor activation in the choroid plexus, allowing for increased CSF secretion into the ventricles invoking increased intracranial pressure (ICP). This theoretical mechanism provides further insight as to the possible underlying pathophysiology of IIH.

Managing idiopathic intracranial hypertension in the eye clinic

Idiopathic intracranial hypertension (IIH) is a neuro-ophthalmological condition characterised by a raised intracranial pressure and papilloedema that causes disabling headaches. The main risk factors of female sex and living with obesity have been known for some time, however the knowledge of the underlying pathophysiology is evolving. Papilloedema can impact the visual function, and the majority of people are offered acetazolamide. Those with sight threatening disease need urgent management, though there is little high quality evidence to recommend any particular surgical intervention. Headache treatment is an unmet clinical need and simple medication overuse advice has the potential to reduce the chronification of migraine-like headaches. IIH is emerging as a systemic metabolic disease distinct from people living with obesity alone. While weight loss is the main stay of disease modifying therapy this is challenging to access and many healthcare professionals that manage the condition have no formal training or accessible pathways for weight management. The aim of this "how to do it" article is to present the latest advances in knowledge of IIH that we pragmatically included in routine clinical care for people living with the condition.

Progress and recognition of idiopathic intracranial hypertension: A narrative review

BACKGROUND

Idiopathic intracranial hypertension (IIH) mainly affects obese young women, causing elevated intracranial pressure, headaches, and papilledema, risking vision loss and severe headaches. Despite weight loss as the primary treatment, the underlying mechanisms remain unclear. Recent research explores novel therapeutic targets.

AIMS

This review aimed to provide a comprehensive understanding of IIH's pathophysiology and clinical features to inform pathogenesis and improve treatment strategies.

METHODS

Recent publications on IIH were searched and summarized using PubMed, Web of Science, and MEDLINE.

RESULTS

The review highlights potential pathomechanisms and therapeutic advances in IIH.

CONCLUSION

IIH incidence is rising, with growing evidence linking it to metabolic and hormonal disturbances. Early diagnosis and treatment remain challenging.

Incretin-Based Multi-Agonist Peptides Are Neuroprotective and Anti-Inflammatory in Cellular Models of Neurodegeneration

Glucagon-like peptide-1 (GLP-1)-based drugs have been approved by the United States Food and Drug Administration (FDA) and are widely used to treat type 2 diabetes mellitus (T2DM) and obesity. More recent developments of unimolecular peptides targeting multiple incretin-related receptors ("multi-agonists"), including the glucose-dependent insulinotropic polypeptide (GIP) receptor (GIPR) and the glucagon (Gcg) receptor (GcgR), have emerged with the aim of enhancing drug benefits. In this study, we utilized human and mouse microglial cell lines, HMC3 and IMG, respectively, together with the human neuroblastoma SH-SY5Y cell line as cellular models of neurodegeneration. Using these cell lines, we studied the neuroprotective and anti-inflammatory capacity of several multi-agonists in comparison with a single GLP-1 receptor (GLP-1R) agonist, exendin-4. Our data demonstrate that the two selected GLP-1R/GIPR dual agonists and a GLP-1R/GIPR/GcgR triple agonist not only have neurotrophic and neuroprotective effects but also have anti-neuroinflammatory properties, as indicated by the decreased microglial cyclooxygenase 2 (COX2) expression, nitrite production, and pro-inflammatory cytokine release. In addition, our results indicate that these multi-agonists have the potential to outperform commercially available single GLP-1R agonists in neurodegenerative disease treatment.

Glucagon-like peptide-1 (GLP-1) receptor agonists for headache and pain disorders: a systematic review

BACKGROUND

Glucagon-like peptide-1 (GLP-1) plays a crucial role in metabolic disorders by enhancing insulin secretion, inhibiting glucagon release, and slowing gastric emptying, thereby improving glycemic control. In recent years, GLP-1 role in neuronal pathways has expanded its therapeutic potential. We aim to comprehensively evaluate the relevance of GLP-1 in headache and pain disorders.

METHODS

A systematic literature search was conducted on PubMed and Embase (Ovid) databases using the search terms "GLP-1" and "pain". Animal and human studies published in English language were included. Abstracts, reviews, and articles on other disorders than "pain" were excluded.

RESULTS

The search strategy identified 833 hits, of which 42 studies were included in the final review. The studies were categorized into four groups: inflammatory pain and osteoarthritis, headaches, neuropathic pain and diabetic neuropathy, and visceral pain and irritable bowel syndrome. GLP-1 receptor (GLP-1R) agonists, like liraglutide, have shown analgesic effects by modulating pain hypersensitivity in animal models of inflammatory and neuropathic pain. GLP-1 is involved in migraine mechanisms and GLP-1R agonists are beneficial in individuals with idiopathic intracranial hypertension. Additionally, GLP-1R agonists reduce visceral hypersensitivity and ameliorate symptoms in patients with irritable bowel syndrome.

CONCLUSIONS

The therapeutic scope of GLP-1R agonists is expanding beyond traditional metabolic targets, highlighting its potential for headache and pain disorders. Engineering bimodal molecules that integrate GLP-1R agonism with specific pain-related mechanisms may offer innovative therapeutic options.

Risk factors and disease associations in people living with idiopathic intracranial hypertension

INTRODUCTION

Idiopathic intracranial hypertension is a neurological condition characterized by a raised intracranial pressure and papilledema, leading to chronic headaches and visual disturbances. By recognizing modifiable risk factors and deploying evidence-based interventions, healthcare providers have the potential to mitigate the burden of the disease and improve patient outcomes.

AREAS COVERED

It is well known that the condition occurs in predominantly pre-menopausal females who live with obesity particularly in the context of recent weight gain. This review discusses what risk factors may contribute to the metabolic underpinnings of cerebrospinal fluid dysregulation. There are a number of disease associations that are important to screen for as they can alter management.

EXPERT OPINION

There is emerging evidence to suggest that idiopathic intracranial hypertension is a systemic metabolic disease and it is unknown what are all the risk factors are that precipitate the condition. Targeting certain hardwired risk factors is unachievable. However, as recent weight gain has been identified as a predominant risk factor for the development of the disease and relapse, modification of body weight should be the primary aim of management. Insightful research into the involvement of the neuroendocrine axis driving cerebrospinal fluid dysregulation now has the potential for the development of therapeutic targets.

Reducing the global burden of cerebral venous thrombosis: An international research agenda

BACKGROUND

Due to the rarity of cerebral venous thrombosis (CVT), performing high-quality scientific research in this field is challenging. Providing answers to unresolved research questions will improve prevention, diagnosis, and treatment, and ultimately translate to a better outcome of patients with CVT. We present an international research agenda, in which the most important research questions in the field of CVT are prioritized.

AIMS

This research agenda has three distinct goals: (1) to provide inspiration and focus to research on CVT for the coming years, (2) to reinforce international collaboration, and (3) to facilitate the acquisition of research funding.

SUMMARY OF REVIEW

This international research agenda is the result of a research summit organized by the International Cerebral Venous Thrombosis Consortium in Amsterdam, the Netherlands, in June 2023. The summit brought together 45 participants from 15 countries including clinical researchers from various disciplines, patients who previously suffered from CVT, and delegates from industry and non-profit funding organizations. The research agenda is categorized into six pre-specified themes: (1) epidemiology and clinical features, (2) life after CVT, (3) neuroimaging and diagnosis, (4) pathophysiology, (5) medical treatment, and (6) endovascular treatment. For each theme, we present two to four research questions, followed by a brief substantiation per question. The research questions were prioritized by the participants of the summit through consensus discussion.

CONCLUSIONS

This international research agenda provides an overview of the most burning research questions on CVT. Answering these questions will advance our understanding and management of CVT, which will ultimately lead to improved outcomes for CVT patients worldwide.

Association between Glucagon-Like Peptide 1 (GLP-1) Receptor Agonists Exposure and Intraocular Pressure Change

Objective

This study aims to provide data on the effects of glucagon-like peptide 1 receptor (GLP-1R) agonists on intraocular pressure (IOP).

Design

Retrospective cohort study.

Subjects Participants and/or Controls

1247 glaucoma surgery and treatment naïve eyes of 626 patients who were initiated on GLP-1R agonists compared to 1083 glaucoma surgery and treatment naïve eyes of 547 patients who were initiated on other oral antidiabetics.

Methods Intervention or Testing

The University of California Health Data Warehouse was queried for patients exposed to GLP-1R agonists or other oral antidiabetics. Index date was defined as the date of first exposure to the medication. Eyes with at least one pre-exposure and one post-exposure tonometry record within 365 days of the index date were included in the analysis. Clinical and laboratory data elements were extracted from the database. Eyes were censored from the analysis upon exposure to glaucoma hypotensive medication or glaucoma surgery. ΔIOP was analyzed using a paired t-test. Regression analysis was conducted using generalized estimating equations (GEE) accounting for inter-eye correlation. Sensitivity analyses were performed to assess the robustness of the findings.

Main Outcome Measures

Primary outcome measure was ΔIOP after exposure to the medication.

Results

The median age of all included subjects was 66.2 years [IQR=18.3]; 607 (51.7%) were female, and 667 (56.9%) were Caucasian. Median pre-exposure IOP, HbA1c, and BMI were 15.2 mmHg [IQR=3.8], 7.5 [IQR=2.4], and 29.8 [IQR=9.4], respectively. 776 individuals (66.1%) had diabetes, with the median number of active oral antidiabetics being 1.0 [IQR=1.0], and 441 (37.5%) being insulin users. Several pre-exposure characteristics significantly differed between the GLP-1R agonist and the control group. The mean ΔIOP was -0.4±2.8 mmHg (paired t-test p<0.001) and -0.2±3.3 mmHg (paired t-test p = 0.297) in the GLP-1R agonist and other antidiabetics groups, respectively. Pre-exposure IOP was the only independent predictor of ΔIOP in multivariable GEE. Sensitivity analyses yielded similar results.

Conclusions

Although GLP-1R agonists were significantly associated with a decrease in IOP in the paired analysis, they were not associated with ΔIOP in multivariable GEE. Moreover, the difference between the ΔIOP in the two groups was small. Future prospective studies following a standardized dose and delivery method may provide further insights.

The Pseudotumor Cerebri Syndrome

Pseudotumor cerebri syndrome is a syndrome of increased cerebrospinal fluid pressure without ventriculomegaly, mass lesion, or meningeal abnormality. It is either primary (idiopathic intracranial hypertension, IIH) or secondary. A secondary cause is unlikely when adhering to the diagnostic criteria. Permanent visual loss occurs if undetected or untreated, and the associated headaches may be debilitating. Fulminant disease may result in blindness despite aggressive treatment. This study addresses the diagnosis and management of IIH including new insights into the pathobiology of IIH, updates in therapeutics and causes of overdiagnosis.

Effect of glucagon like peptide-1 receptor agonist exenatide, used as an intracranial pressure lowering agent, on cognition in Idiopathic Intracranial Hypertension

BACKGROUND

Cognitive function can be affected in conditions with raised intracranial pressure (ICP) such as idiopathic intracranial hypertension (IIH). Drugs used off label to treat raised ICP also have cognitive side effects, underscoring the unmet need for effective therapeutics which reduce ICP without worsening cognition. The Glucagon Like Peptide-1 (GLP-1) receptor agonist, exenatide, has been shown to significantly reduce ICP in IIH, therefore this study aimed to determine the effects of exenatide on cognition in IIH.

METHODS

This was an exploratory study of the IIH:Pressure trial (ISTCRN 12678718). Women with IIH and telemetric ICP monitors (n = 15) were treated with exenatide (n = 7) or placebo (n = 8) for 12 weeks. Cognitive function was tested using the National Institute of Health Toolbox Cognitive Battery at baseline and 12 weeks.

RESULTS

Cognitive performance was impaired in fluid intelligence ((T-score of 50 = population mean), mean (SD) 37.20 (9.87)), attention (33.93 (7.15)) and executive function (38.07 (14.61)). After 12-weeks there was no evidence that exenatide compromised cognition (no differences between exenatide and placebo). Cognition improved in exenatide treated patients in fluid intelligence (baseline 38.4 (8.2), 12 weeks 52.9 (6.6), p = 0.0005), processing speed (baseline 43.7 (9.4), 12 weeks 58.4 (10.4), p = 0.0058) and episodic memory (baseline 49.4 (5.3), 12 weeks 62.1 (13.2), p = 0.0315).

CONCLUSIONS

In patients with raised ICP due to IIH, exenatide, a drug emerging as an ICP lowering agent, does not adversely impact cognition. This is encouraging and has potential to be relevant when considering prescribing choices to lower ICP.

Understanding the pathophysiology of idiopathic intracranial hypertension (IIH): a review of recent developments

Idiopathic intracranial hypertension (IIH) is a condition of significant morbidity and rising prevalence. It typically affects young people living with obesity, mostly women of reproductive age, and can present with headaches, visual abnormalities, tinnitus and cognitive dysfunction. Raised intracranial pressure without a secondary identified cause remains a key diagnostic feature of this condition, however, the underlying pathophysiological mechanisms that drive this increase are poorly understood. Previous theories have focused on cerebrospinal fluid (CSF) hypersecretion or impaired reabsorption, however, the recent characterisation of the glymphatic system in many other neurological conditions necessitates a re-evaluation of these hypotheses. Further, the impact of metabolic dysfunction and hormonal dysregulation in this population group must also be considered. Given the emerging evidence, it is likely that IIH is triggered by the interaction of multiple aetiological factors that ultimately results in the disruption of CSF dynamics. This review aims to provide a comprehensive update on the current theories regarding the pathogenesis of IIH.

Diagnosis and treatment of disorders of intracranial pressure: consensus statement of the Spanish Society of Neurology's Headache Study Group

Primary intracranial pressure disorders include idiopathic intracranial hypertension and spontaneous intracranial hypotension. Remarkable advances have been made in the diagnosis and treatment of these 2entities in recent years. Therefore, the Spanish Society of Neurology's Headache Study Group (GECSEN) deemed it necessary to prepare this consensus statement, including diagnostic and therapeutic algorithms to facilitate and improve the management of these disorders in clinical practice. This document was created by a committee of experts belonging to GECSEN, and is based on a systematic review of the literature, incorporating the experience of the participants, and establishes practical recommendations with levels of evidence and grades of recommendation.

Normative body mass-adjusted reference ranges of magnetic resonance imaging signs commonly used in diagnosing idiopathic intracranial hypertension in a healthy standard population

Patients with chronic daily headaches (CDH) are often a diagnostic challenge and frequently undergo neuroimaging. One common underlying cause of CDH is idiopathic intracranial hypertension (IIH). However, certain neuroimaging abnormalities that suggest IIH, such as optic nerve sheath diameters (ONSD), pituitary gland height, and venous sinus diameter, require interpretation due to the absence of established normative values. Notably, intracranial pressure is known to varies with age, sex and weight, further complicating the determination of objectively abnormal findings within a specific patient group. This study aims to assist clinical neuroradiologists in differentiating neuroimaging results in CDH by providing weight-adjusted normative values for imaging characteristics of IIH. In addition to age and BMI we here assessed 1924 population-based T1-weighted MRI datasets of healthy participants for relevant MRI aspects of IIH. Association to BMI was analyzed using linear/logistic regression controlled for age and stratified for sex. ONSD was 4.3 mm [2.8; 5.9]/4.6 mm [3.6; 5.7] and diameter of transverse sinus was 4.67 mm [1.6; 6.5]/4.45 mm [3.0; 7.9]. Height of pituitary gland was 5.1 mm [2.2;8.1]/4.6 mm [1.9;7.1] for female and male respectively. Values generally varied with BMI with regression slopes spanning 0.0001 to 0.05 and were therefor presented as normative values stratified by BMI. Protrusion of ocular papilla, empty sella and transverse sinus occlusion were rare in total. Our data show an association between BMI and commonly used MRI features for diagnosing IIH. We provide categorized normative BMI values for ONSD, pituitary gland height, and transverse sinus diameter. This distinction helps objectively identify potential IIH indicators compared to regular population norms, enhancing diagnostic accuracy for suspected IIH patients. Notably, optic nerve head protrusion, empty sella, and transverse sinus occlusion are rare in healthy individuals, solidifying their importance as imaging markers regardless of BMI.

Prevention of cardiorenal complications in people with type 2 diabetes and obesity

Traditional approaches to prevention of the complications of type 2 diabetes (T2D) and obesity have focused on reduction of blood glucose and body weight. The development of new classes of medications, together with evidence from dietary weight loss and bariatric surgery trials, provides new options for prevention of heart failure, chronic kidney disease, myocardial infarction, stroke, metabolic liver disease, cancer, T2D, and neurodegenerative disorders. Here I review evidence for use of lifestyle modification, SGLT-2 inhibitors, GLP-1 receptor agonists, selective mineralocorticoid receptor antagonists, and bariatric surgery, for prevention of cardiorenal and metabolic complications in people with T2D or obesity, highlighting the contributions of weight loss, as well as weight loss-independent mechanisms of action. Collectively, the evidence supports a tailored approach to selection of therapeutic interventions for T2D and obesity based on the likelihood of developing specific complications, rather than a stepwise approach focused exclusively on glycemic or weight control.

Idiopathic intracranial hypertension: a step change in understanding the disease mechanisms

The understanding of idiopathic intracranial hypertension (IIH) has evolved over the past few years. Previously, IIH was considered a disease exclusively affecting the neuro-ophthalmic axis, characterized by raised intracranial pressure, headache and papilloedema, and resulting in the risk of severe and permanent visual loss and life-changing disabling headaches. Recent advances have begun to redefine IIH as a probable metabolic disease involving a range of systemic manifestations. More than 95% of individuals affected by the disease are women of reproductive age with obesity. The incidence is rapidly rising and parallels the escalating worldwide obesity rates. Contemporary insights identify associations with insulin resistance, type 2 diabetes and a twofold increased risk of cardiovascular disease in excess of that driven by obesity alone. Adipose distribution in people with IIH, like that in other metabolic diseases, is preferentially centripetal and is associated with changes in intracranial pressure. Evidence now demonstrates adipose tissue dysfunction in people with IIH, involving transcriptional and metabolic priming for lipogenesis and weight gain. Hormonal perturbations are also observed, including a unique phenotype of androgen excess that promotes cerebrospinal fluid secretion. Knowledge of these additional disease features is driving research into novel therapeutic targets and altering the approach to multidisciplinary care.

The Impact of Valsalva Manoeuvres and Exercise on Intracranial Pressure and Cerebrovascular Dynamics in Idiopathic Intracranial Hypertension

Idiopathic intracranial hypertension (IIH) is a disease characterised by elevated intracranial pressure (ICP). The impact of straining and exercise on ICP regulation is poorly understood yet clinically relevant to IIH patient care. We sought to investigate the impact of Valsalva manoeuvres (VMs) and exercise on ICP and cerebrovascular haemodynamics in IIH. People with IIH were prospectively enrolled and had an intraparenchymal telemetric ICP sensor inserted. Three participants (age [mean ± standard deviation]: 40.3 ± 13.9 years) underwent continuous real-time ICP monitoring coupled with cerebrovascular haemodynamic assessments during VMs and moderate exercise. Participants had IIH with supine ICP measuring 15.3 ± 8.7 mmHg (20.8 ± 11.8 cm cerebrospinal fluid (CSF)) and sitting ICP measuring -4.2 ± 7.9 mmHg (-5.7 ± 10.7 cmCSF). During phase I of a VM ICP increased by 29.4 ± 13.5 mmHg (40.0 ± 18.4 cmCSF) but returned to baseline within 16 seconds from VM onset. The pattern of ICP changes during the VM phases was associated to that of changes in blood pressure, the middle cerebral artery blood velocity and prefrontal cortex haemodynamics. Exercise led to minimal effects on ICP. In conclusion, VM-induced changes in ICP were coupled to cerebrovascular haemodynamics and showed no sustained impact on ICP. Exercise did not lead to prolonged elevation of ICP. Those with IIH experiencing VMs (for example, during exercise and labour) may be reassured at the brief nature of the changes. Future research must look to corroborate the findings in a larger IIH cohort.

Weight Management Interventions for Adults With Idiopathic Intracranial Hypertension: A Systematic Review and Practice Recommendations

BACKGROUND AND OBJECTIVES

Idiopathic intracranial hypertension (IIH) is associated with obesity; however, there is a lack of clinical consensus on how to manage weight in IIH. The aim of this systematic review was to evaluate weight loss interventions in people with IIH to determine which intervention is superior in terms of weight loss, reduction in intracranial pressure (ICP), benefit to visual and headache outcomes, quality of life, and mental health.

METHODS

A systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and registered with PROSPERO (CRD42023339569). MEDLINE and CINAHL were searched for relevant literature published from inception until December 15, 2022. Screening and quality appraisal was conducted by 2 independent reviewers. Recommendations were graded using Scottish Intercollegiate Guidelines Network methodology.

RESULTS

A total of 17 studies were included. Bariatric surgery resulted in 27.2-27.8 kg weight loss at 24 months (Level 1- to 1++). Lifestyle weight management interventions resulted in between 1.4 and 15.7 kg weight loss (Level 2+ to 1++). Bariatric surgery resulted in the greatest mean reduction in ICP (-11.9 cm H2O) at 24 months (Level 1++), followed by multicomponent lifestyle intervention + acetazolamide (-11.2 cm H2O) at 6 months (Level 1+) and then a very low-energy diet intervention (-8.0 cm H2O) at 3 months (Level 2++). The least ICP reduction was shown at 24 months after completing a 12-month multicomponent lifestyle intervention (-3.5 cm H2O) (Level 1++). Reduction in body weight was shown to be highly correlated with reduction in ICP (Level 2++ to 1++).

DISCUSSION

Bariatric surgery should be considered for women with IIH and a body mass index (BMI) ≥35 kg/m2 since this had the most robust evidence for sustained weight management (grade A). A multicomponent lifestyle intervention (diet + physical activity + behavior) had the most robust evidence for modest weight loss with a BMI <35 kg/m2 (grade B). Longer-term outcomes for weight management interventions in people with IIH are required to determine whether there is a superior weight loss intervention for IIH.

Determining the role of novel metabolic pathways in driving intracranial pressure reduction after weight loss

Idiopathic intracranial hypertension, a disease classically occurring in women with obesity, is characterized by raised intracranial pressure. Weight loss leads to the reduction in intracranial pressure. Additionally, pharmacological glucagon-like peptide-1 agonism reduces cerebrospinal fluid secretion and intracranial pressure. The potential mechanisms by which weight loss reduces intracranial pressure are unknown and were the focus of this study. Meal stimulation tests (fasted plasma sample, then samples at 15, 30, 60, 90 and 120 min following a standardized meal) were conducted pre- and post-bariatric surgery [early (2 weeks) and late (12 months)] in patients with active idiopathic intracranial hypertension. Dynamic changes in gut neuropeptides (glucagon-like peptide-1, gastric inhibitory polypeptide and ghrelin) and metabolites (untargeted ultra-high performance liquid chromatography-mass spectrometry) were evaluated. We determined the relationship between gut neuropeptides, metabolites and intracranial pressure. Eighteen idiopathic intracranial hypertension patients were included [Roux-en-Y gastric bypass (RYGB) n = 7, gastric banding n = 6 or sleeve gastrectomy n = 5]. At 2 weeks post-bariatric surgery, despite similar weight loss, RYGB had a 2-fold (50%) greater reduction in intracranial pressure compared to sleeve. Increased meal-stimulated glucagon-like peptide-1 secretion was observed after RYGB (+600%) compared to sleeve (+319%). There was no change in gastric inhibitory polypeptide and ghrelin. Dynamic changes in meal-stimulated metabolites after bariatric surgery consistently identified changes in lipid metabolites, predominantly ceramides, glycerophospholipids and lysoglycerophospholipids, which correlated with intracranial pressure. A greater number of differential lipid metabolites were observed in the RYGB cohort at 2 weeks, and these also correlated with intracranial pressure. In idiopathic intracranial hypertension, we identified novel changes in lipid metabolites and meal-stimulated glucagon-like peptide-1 levels following bariatric surgery which were associated with changes in intracranial pressure. RYGB was most effective at reducing intracranial pressure despite analogous weight loss to gastric sleeve at 2 weeks post-surgery and was associated with more pronounced changes in these metabolite pathways. We suggest that these novel perturbations in lipid metabolism and glucagon-like peptide-1 secretion are mechanistically important in driving a reduction in intracranial pressure following weight loss in patients with idiopathic intracranial hypertension. Therapeutic targeting of these pathways, for example with glucagon-like peptide-1 agonist infusion, could represent a therapeutic strategy.

A Neuro-Ophthalmologist's Guide to Advances in Intracranial Pressure Measurements

Cerebrospinal fluid disorders have a wide-ranging impact on vision, headache, cognition and a person's quality of life. Due to advances in technology and accessibility, intracranial pressure measurement and monitoring, usually managed by neurosurgeons, are being employed more widely in clinical practice. These developments are of direct importance for Ophthalmologists and Neurologists because the ability to readily measure intracranial pressure can aide management decisions. The aim of this review is to present the emerging evidence for intracranial pressure measurement methods and interpretation that is relevant to Neuro-ophthalmologists.

Guidelines of the International Headache Society for Controlled Clinical Trials in Idiopathic Intracranial Hypertension

The quality of clinical trials is essential to advance treatment, inform regulatory decisions and meta-analysis. With the increased incidence of idiopathic intracranial hypertension and the emergence of clinical trials for novel therapies in this condition, the International Headache Society Guidelines for Controlled Clinical Trials in Idiopathic Intracranial Hypertension aims to establish guidelines for designing state-of-the-art controlled clinical trials for idiopathic intracranial hypertension.

Treatment with GLP-1 receptor agonists is associated with significant weight loss and favorable headache outcomes in idiopathic intracranial hypertension

BACKGROUND

In idiopathic intracranial hypertension (IIH), sustained weight loss is the main pillar in modifying disease course, whereby glucagon-like peptide-1 receptor agonists (GLP-1-RAs) could present an attractive treatment option.

METHODS

In this open-label, single-center, case-control pilot study, patients with IIH (pwIIH) and a body mass index (BMI) of ≥ 30 kg/m² were offered to receive a GLP-1-RA (semaglutide, liraglutide) in addition to the usual care weight management (UCWM). Patients electing for UCWM only served as a control group matched for age-, sex- and BMI (1:2 ratio). The primary endpoint was the percentage weight loss at six months (M6) compared to baseline. Secondary endpoints included the rate of patients with a weight loss of ≥ 10%, monthly headache days (MHD), the rate of patients with a ≥ 30% and ≥ 50% reduction in MHD, visual outcome parameters, and adverse events (AEs).

RESULTS

We included 39 pwIIH (mean age 33.6 years [SD 8.0], 92.3% female, median BMI 36.3 kg/m² [IQR 31.4-38.3]), with 13 patients being treated with GLP-1-RAs. At M6, mean weight loss was significantly higher in the GLP-1-RA group (-12.0% [3.3] vs. -2.8% [4.7]; p < 0.001). Accordingly, weight loss of ≥ 10% was more common in this group (69.2% vs. 4.0%; p < 0.001). Median reduction in MHD was significantly higher in the GLP-1-RA group (-4 [-10.5, 0.5] vs. 0 [-3, 1]; p = 0.02), and the 50% responder rate was 76.9% vs. 40.0% (p = 0.04). Visual outcome parameters did not change significantly from baseline to M6. Median reduction in acetazolamide dosage was significantly higher in the GLP-1-RA group (-16.5% [-50, 0] vs. 0% [-25, 50]; p = 0.04). AEs were mild or moderate and attributed to gastrointestinal symptoms in 9/13 patients. None of the AEs led to premature treatment discontinuation.

CONCLUSIONS

This open-label, single-center pilot study suggests that GLP-1-RAs are an effective and safe treatment option for achieving significant weight loss with a favorable effect on headache, leading to reduced acetazolamide dosage in pwIIH.

Experimental drugs for the treatment of idiopathic intracranial hypertension (IIH): shedding light on phase I and II trials

INTRODUCTION

Idiopathic intracranial hypertension is a neurological condition characterized by a raised intracranial pressure and papilledema that causes debilitating headaches. While the extent of the pathophysiology is being discovered, the condition is emerging as a systemic metabolic disease distinct to people living with obesity alone. Idiopathic intracranial hypertension is becoming more common and therefore establishing licensed therapeutics is a key priority.

AREA COVERED

The translation of preclinical work in idiopathic intracranial hypertension is evident by the two early phase trials evaluating 11-β-hydroxysteroid dehydrogenase inhibitor, AZD4017, and a glucagon like peptide-1 receptor agonist, Exenatide. This review summarizes these two early phase trials evaluating targeted medicines for the treatment of intracranial pressure. The modulation of these two distinct mechanisms have potential for therapeutic intervention in people living with idiopathic intracranial hypertension.

EXPERT OPINION

The clinical trial landscape in idiopathic intracranial hypertension is a challenge due to the rarity of the disease and the lack of agreed meaningful trial outcomes. Further preclinical work to fully understand the pathogenesis is required to enable personalized targeted drug treatment.

Topical and systemic GLP-1R agonist administration both rescue retinal ganglion cells in hypertensive glaucoma

Glaucomatous neurodegeneration, a blinding disease affecting millions worldwide, has a need for the exploration of new and effective therapies. Previously, the glucagon-like peptide-1 receptor (GLP-1R) agonist NLY01 was shown to reduce microglia/macrophage activation, rescuing retinal ganglion cells after IOP elevation in an animal model of glaucoma. GLP-1R agonist use is also associated with a reduced risk for glaucoma in patients with diabetes. In this study, we demonstrate that several commercially available GLP-1R agonists, administered either systemically or topically, hold protective potential in a mouse model of hypertensive glaucoma. Further, the resulting neuroprotection likely occurs through the same pathways previously shown for NLY01. This work contributes to a growing body of evidence suggesting that GLP-1R agonists represent a viable therapeutic option for glaucoma.