Intranasal Insulin for Improving Cognitive Function in Multiple Sclerosis

Cognitive impairment is common in and devastating to people with MS. MS is a common, chronic, central nervous system (CNS) disease characterized by inflammation, demyelination, and neurodegeneration. One of the most devastating symptoms of this disease is impaired cognitive function, which is common and present in over 60% of individuals with MS. MS-related cognitive impairment is associated with lowered quality of life and reduced functional capacity, including loss of employment, impaired social relationships, compromised driving safety, and poor adherence to treatment. Impaired cognitive functioning has been observed early in the disease, sometimes even before diagnosis, and cognitive function has been shown to decline longitudinally, both over the short- and long-term. Several cognitive domains are impacted in people with MS, including attention, memory, executive functioning, and especially processing speed.

To date, multiple pharmacologic interventions have been assessed with disappointing results. There was no significant difference between treatment and placebo for cognition in randomized control trials of donepezil, aminopyridines, gingko biloba, and memantine. Psychostimulants demonstrated some efficacy, but only in secondary outcome measures. Behavioral interventions show promise but are understudied. Furthermore, cognitive rehabilitation is often time consuming, costly, and not universally available. Hence, there is an urgent need to identify or develop novel therapies that can help improve cognitive function in MS.

Intranasal insulin is extremely safe and tolerable in other populations, allowing for concentrated delivery to the nervous system. An intranasal delivery system provides a non-invasive way to bypass the blood-brain barrier and allow rapid delivery of a medication to the CNS via the olfactory and trigeminal perivascular channels.The main advantage of the delivery system is reducing systemic side effects via limiting a medication's exposure to peripheral organs and tissues.

Insulin administration has been shown to improve memory and learning in healthy people and in those with neurodegenerative diseases. Intranasal insulin has been shown to have neuroprotective and restorative effects in several human clinical trials. Overall, findings suggest that intranasal insulin not only affects cognitive function acutely, but that over time, there may be associated structural changes that lead to a more permanent treatment benefit. Cognitive dysfunction is very common in MS and can be devastating, therefore a treatment intervention (i.e., intranasal insulin) can help both acutely and longitudinally.

The primary aim of this study is to assess the safety and tolerability of intranasal insulin in people with MS. The secondary aim is to evaluate if intranasal insulin improves learning and memory in people with MS. The third aim is to evaluate the impact of intranasal insulin on measures of oxidative stress, axonal injury, cellular stress, and energy metabolism in MS.