Prolactin and Multiple Sclerosis
The question about the relationship between prolactin and multiple sclerosis is one that numerous researchers have been trying to answer. What do we know about the potential benefits or disadvantages of this hormone when it comes to MS?
Prolactin is a hormone that is produced by the pituitary gland. Its function in women is to stimulate breast development and milk production, but thus far there is no known normal function for the hormone in men.
Prolactin and multiple sclerosis
An interesting observation about prolactin and multiple sclerosis in pregnant women is that levels of the hormone peak during the trimester of pregnancy, at about the same time MS tends to go into remission. This prolactin and multiple sclerosis relationship continues when women choose to breastfeed.
Breastfeeding stimulates additional release of prolactin while levels decline in women who do not breastfeed. A meta-analysis has shown that women with MS who breastfed were nearly half as likely to experience a post-partum relapse when compared with women who did not breastfeed.
One positive findings concerning prolactin and MS has been seen in animals. Such studies have indicated that prolactin may help repair (remyelinate) damaged nerve cells.
More specifically, the research showed that prolactin promoted the proliferation of oligodendrocyte precursors (oligodendrocytes are involved in myelin production) and oligodendrocyte generation in mouse spinal cords. This finding suggests the hormone could be used as a treatment option for people with multiple sclerosis.
In other research, University of Calgary scientists used an animal model of MS (experimental autoimmune encephalomyelitis, EAE) to evaluate the use of prolactin alone, interferon-beta alone, a combination of the agents, and no treatment. In this case, the combination of prolactin and interferon-B resulted in greater reduction of clinical signs of EAE when compared to either treatment alone or to controls.
A 2014 case-control study looked at the role of hyperprolactinemia (elevated prolactin levels) in multiple sclerosis. A total of 22 individuals with MS and hyperprolactinemia and 66 patients with MS but no hyperprolactinemia were evaluated.
The authors noted:
- A statistically significant greater value of relapse rate among MS patients with elevated prolactin when compared with controls.
- The difference in the Expanded Disability Status Scale (EDSS) scores was statistically significant in favor of the MS patients with hyperprolactemia.
- Overall, the authors concluded that their findings “suggested a protective role of prolactin in demyelinating procedure of MS”
Downside of prolactin and MS
Prolactin may also have a downside regarding MS. In a systemic review of 23 studies of prolactin and multiple sclerosis, the reviewers found that
- Elevated levels of prolactin seems to be more common in people with multiple sclerosis than those without the disease
- Most people with multiple sclerosis have normal prolactin levels
- Elevated prolactin levels may be associated with clinical relapse in MS, especially among individuals who have optic neuritis or hypothalamic lesions, although experts don’t know whether this relationship is a cause or consequence of a relapse
- For now, the impact of prolactin levels on the outcome of MS is unclear
Could prolactin play a positive role in multiple sclerosis? For now, the answer to this question is unclear. However, it is an agent of interest in the continuing quest to better understand and tackle this disease.
Also read about alternative treatments for multiple sclerosis
Etemadifar M et al. Multiple sclerosis and hyperprolactinemia: a case-control study. Acta Neurologica Belgica 2014 Dec 14
Gregg C et al. White matter plasticity and enhanced remyelination in the maternal CNS. Journal of Neuroscience 2007;27:1812–23.
Pakpoor J et al. Breastfeeding and multiple sclerosis relapses: a meta-analysis. Journal of Neurology 2012;259:2246Y2248.
Zhornitsky S et al. Prolactin in combination with interferon-B reduces disease severity in an animal model of multiple sclerosis. Journal of Neuroinflammation 2015 Mar 19; 12:55
Zhornitsky S et al. Prolactin in multiple sclerosis. Multiple Sclerosis 2013 Jan; 19(1): 15-23