Like Alzheimer’s disease, multiple sclerosis (MS) disproportionately impacts women and can affect societal roles and norms, both at home and in the workplace. In addition, lifestyle factors also play a key role in disease outcomes. Fortunately, unlike Alzheimer’s disease, the field of MS therapeutics has seen an explosion of new disease modifying therapies with many experts believing lessons learned can help advance Alzheimer’s drug development.
Mary Rensel, MD is neurologist at the Mellen Center for MS at Cleveland Clinic. She joined us this National Multiple Sclerosis Awareness Month to take a closer look at the similarities of these diseases, the role of gender and how MS might provide hope for the future of Alzheimer’s treatment.
Read the Q&A with Dr. Rensel below.
WAM: MS is an autoimmune disease, with more research pointing to Alzheimer’s disease being one, too. What are the biological similarities between these two diseases
Dr. Rensel: Multiple sclerosis (MS) and Alzheimer’s disease (AD) both cause changes to the brain and can cause a person to lose their ability to fully function. They both affect millions of people and there are no cures for either disease. MS typically causes symptoms when people are 20-40 years of age, it has been reported in young children and teens as well whereas AD tends to start when people are in their fifties and older. Both processes, MS and AD, trigger neurotoxicity, local inflammation which can lead to nerve damage. Nerve damage can lead to deficiencies and imbalances with the neurotransmitters and thereby cause nerve dysfunction and neurologic symptoms like memory impairment. The other similarity is there is speculation that both diseases are caused by or are worsened by viral infections, such as Epstein Barr Virus, or mono virus, in MS and HSV, or herpes virus, in AD. More research is needed to fully understand these infections’ relationship between MS and AD.
WAM: Why do women develop MS at a much higher rate than men? What makes women more susceptible?
Dr. Rensel:We are not certain why women develop MS at higher rates, but do know reproductive hormones, environmental exposures, and lifestyle patterns all play a role. MS, like other autoimmune diseases, is more prevalent in women than men, this difference is seen at puberty. Before puberty boys and girls have MS at even rates. Likely the reproductive hormones influence the risk of autoimmune diseases. Adults have difference responses to environmental factors such as Vitamin D and sunlight exposure which may also influence the risk of MS.
WAM: Many of the symptoms of MS – numbness, weakness, fatigue – are invisible. How do these symptoms impact women’s roles at home and in the workplace?
Dr. Rensel: The “invisible” symptoms of MS are quite common and can impact the lives of those living with MS each day. When a person is fatigued, they may need to pace their day or miss their children’s events due to limited endurance and weakness. MS can lead to poor endurance where a person can walk a block, yet is not able to walk many blocks. This can then change their ability to enjoy a walk in the park or an outing with their families. This fatigue and other symptoms can also affect workplace functioning, when one is tired and needs a daily nap in the afternoon, it can make working a full-time job quite difficult.
WAM: MS drug development has seen the most advancements over the last 30 years than any other neurological disorder. How are these advancements being used to inform Alzheimer’s drug development? What are the big lessons learned?
Dr. Rensel: It has been an exciting time, the last 30 years, treating MS. I now regularly hear from my patients that they “forget they have MS,” since the medications work well and are relatively safe to remain on for decades. More details have been uncovered regarding the immune response in and around the brain that have helped researchers develop new medications for MS. This knowledge can also be used to guide Alzheimer’s treatments as we now know more about the lymphatic system around the brain as well as how immune cells enter and effect the brain and its support structures.
WAM: Do we know lifestyle plays a role in risk reduction for Alzheimer’s, can the same be said for MS? Or is lifestyle only a factor in disease management? Are there any external factors that can impact MS risk?
Dr. Rensel: Pediatric MS patients and their families who have participated in clinical trials have helped answer many of these questions. To date we have learned that pesticides, air quality, smoking exposure, obesity and the Epstein Barr Virus all influence the age of onset of MS. Studies in adult MS patients have clarified that smoking causes more gait disorders and brain scarring and that having multiple vascular risk factors like diabetes, high cholesterol or high blood pressure can increase your risk of gait disability by over 200%. These lifestyle factors and comorbidities influence the disability levels of our patients with MS.