In April 2022, Dr. Adrián Alambiaga successfully defended his doctoral thesis at CEU Cardenal Herrera University. His thesis centered around the exploration of progesterone as a way to stop cell death from oxidative stress, particularly related to vision loss and retinitis pigmentosa (RP). As reported in News Medical, Dr. Alambiaga and his research team found that topical progesterone on the eye halted the progression of photoreceptor cell death in mice. While more research is needed in the future, this does show promise for the future of retinitis pigmentosa treatment.
To learn more about the research, take a look at the study published in Pharmaceuticals.
What is Retinitis Pigmentosa (RP)?
Retinitis pigmentosa (RP) is an umbrella term for a group of inherited eye diseases which cause retinal degeneration. Normally, the retina helps convert light into electrical signals. The brain reads and interprets these as vision. However, patients with RP experience photoreceptor cell degeneration, causing progressive vision loss. There are over 60 different gene mutations associated with retinitis pigmentosa. Different forms may be inherited in an autosomal dominant, autosomal recessive, and X-linked pattern. Symptoms vary based on whether rods or cones are initially involved. However, as the condition progresses, symptoms can include:
- A loss of peripheral and night vision
- Diminished central vision, color perception, and visual acuity
- Night blindness
Many people with RP are considered legally blind before 40 years old.
Dr. Alambiaga’s Research into Progesterone
To begin, let’s first take a look at what progesterone is. According to HealthyWomen, progesterone is:
a hormone that stimulates and regulates important functions, playing a role in maintaining pregnancy, preparing the body for conception, and regulating the monthly menstrual cycle.
Progesterone is naturally produced in the ovaries and adrenal glands. However, it may also be given as a medication to help reduce abnormal uterine lining thickening, or to help reduce the risk of certain cancers.
Dr. Alambiaga recognized that prior studies potentially associated progesterone as a way to reduce oxidative stress and prevent cell death. However, he felt that oral progesterone would be ineffective for treating retinitis pigmentosa, as even large amounts taken orally would have minimal effects on the eye. So, his research evaluated other forms of topical progesterone administration that would effectively deliver the treatment directly to the eye.
Some of the options Dr. Alambiaga explored were ocular inserts and eye drops. He found that eye drops were effective and could get through both the sclera and the cornea. However, he discovered that ocular inserts were the most effective treatment measure. In the mice models, the ocular inserts allowed sustained delivery of progesterone to the neuroretina, required less frequent treatment administration, and were neither irritating nor toxic. This treatment also protected photoreceptor cells.
