Testosterone and estrogen in multiple sclerosis: from pathophysiology to therapeutics

ABSTRACT

Introduction: Neuroprotection and remyelination are two unmet needs in the treatment of multiple sclerosis (MS). Therapeutic potential has been identified with sexual hormones, supported in women by a decrease in MS activity during the pregnancy, in men by a greater severity of symptoms and a faster progression than in women.

Areas covered: The therapeutic effect of testosterone and estrogens is reviewed. Both hormones have demonstrated an anti-inflammatory effect. Testosterone has an effect in protecting neurons in culture against glutamate-induced toxicity and oxidative stress, and stimulates myelin formation and regeneration mediated through the neural androgen receptor. In experimental autoimmune encephalomyelitis model, estrogens significantly decrease inflammation in the central nervous system via ERα, while its action on ERβ leads to myelin and axon reparation. Estriol therapy in two phase 2 trials showed a decrease in clinical disease activity and inflammatory parameters in MRI. However, evidence of a therapeutic effect of testosterone is scarce.

Expert commentary: Phase 3 trials with estriol as an add-on supplementation are now mandatory. Testosterone is another candidate to be tested in phase 2 trials. These hormones should be considered as an adjunctive therapy. New validated tools are needed to assess their effect on neuroprotection and remyelination.

KEYWORDS:

• Estrogen
• multiple sclerosis
• neuroinflammation
• neuroprotection
• remyelination
• testosterone

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

One reviewer is a patent holder for a treatment discussed in this paper but have no other relevant financial relationships to disclose.

Additional information

Funding

This paper was not funded.