Researchers at the University of Athens Medical School in Greece have found that people with early stage multiple sclerosis (MS) and overactive bladder (OAB) have reductions in brain serotonin and a stress-related hormone, cortisol. Serotonin is a chemical that helps nerve cells to communicate. The study, titled “Neurochemical and neuroendocrine correlates of overactive bladder at first demyelinating episode“ appeared July 30th in the journal Neurourology and Urodynamics.

MS is a debilitating, progressive disease of the nervous system. It is caused by an immune attack on the body’s own myelin, a fatty substance that wraps around nerve cells and allows them to conduct impulses and communicate. When myelin is lost, areas of damage called “demyelination” result, which appear in the brain and spinal cord without warning and cause loss of movement, vision, pain and problems with sensation.

Bladder problems such as urinary incontinence also occur frequently in people with MS, with approximately 75% of individuals with MS suffering from this problem. In fact, OAB may be a sign of a first MS episode.

The control of urination is complicated and involves many different components of the nervous system, including the brain, spinal cord and peripheral nervous system. Problems with urination are also experienced by people with anxiety and depression, which are conditions that are more prevalent in people with MS.

The scientists, led by Georgios Koutsis of the Department of Neurology, University of Athens Medical School, were interested in understanding what biological markers are associated with early stage MS and OAB. They studied 101 people with MS and a first demyelinating episode, which is an initial sign of MS onset. They assessed the study participants for signs of OAB and measured several biomarkers in the cerebral spinal fluid of these individuals. The biomarkers included neurotransmitters as well as stress hormones.

Overall, 15 study subjects (15%) had OAB. In those people a breakdown product of the neurotransmitter serotonin (5-HIAA) was reduced when compared to people who did not have OAB. These subjects also had lower levels of the stress hormone cortisol.

In their report, the scientists state “MS patients with OAB syndrome at the first demyelinating episode show reductions in central serotonergic activity and stress hormones. Whether the same changes persist at later disease stages remains to be investigated.”

In future studies the investigators will examine whether these decreases also continue in people with OAB at later MS stages. The biomarkers could potentially be used clinically to identify people with MS and OAB and also to indicate a subgroup of those individuals who have MS.