mTOR inhibitor rapamycin (sirolimus) as a treatment option for tuberous sclerosis

Tuberous sclerosis is a very complex, incurable genetic disease. Within Germany, around 8,000 people are affected, and one to two million people worldwide.

Tuberous sclerosis affects almost all organs. It leads, for example, to benign tumors or malformations in the brain. In addition, renal angiomyolipomas often form. These are also benign tumors of the kidney with a high lipid content, which develop as the most common kidney manifestation in up to 75% of patients.

About 15% of those affected develop subependymal giant cell astrocytomas. These benign neoplasms are located under the wall lining of the cerebral ventricles. They can lead to neurological complications by disrupting cerebrospinal fluid circulation.
Much more frequently, in about 90% of cases, complicated symptomatic epilepsies occur. Therapies with antiepileptic drugs cannot always guarantee freedom from seizures.

Harmless but disturbing skin changes

In tuberous sclerosis, in addition to the nervous system, the skin is also affected. These symptoms are harmless to patients, but often cosmetically disturbing.

Known symptoms include:

Hypomelanotic spots: The so-called “white spots” can be observed in almost all patients. They become visible in the course of the first year of life, with increasing skin pigmentation.

Facial angiofibromas: The first signs of facial angiofibromas are initially small red spots that develop into small warts. These turn red when there is a lot of blood flow to the face. These nodules, which can be up to 4 mm in size, can be found especially on the nose, cheeks and chin area. They may contain small vasodilations that bleed quickly with minor injuries.

Angiofibromas are not dangerous, but due to their abnormality they are cosmetically disturbing for the patient. So far, various treatment methods are available, such as laser sclerotherapy, surgical removal or cryotherapy. Unfortunately, the treatment usually has to be repeated after some time, as the success of the therapy is not permanent.

Fibrous plaques: These symptoms occur primarily on the forehead and scalp. These connective tissue proliferations show up as skin-colored to reddish elevations, which can reach a diameter of up to several centimeters. This change is also considered harmless.
Cobblestone moles: This skin lesion develops in every second patient by the age of ten. They typically occur on the lower back and give the impression that small paving stones have been placed together. This proliferation of connective tissue is also harmless.
Nail fold fibromas: The skin-colored nodules that form at the lateral edges of the nail do not appear until after the age of ten. The changes are particularly common on the toes, less so on the fingers. They often lead to pressure pain in the shoe, bleed or become inflamed.

Skin cream with rapamycin shows effect against skin changes on the face

Scientists at the University of Texas in Houston developed a skin cream with the active ingredient rapamycin. This is effective against the benign but cosmetically disturbing skin changes in nine out of ten cases.
In one study, patients applied the skin cream daily before going to bed for six months. In about 80% of the patients, the appearance of the skin improved noticeably.
Systemic therapy as a solution or tablet should only be considered in particularly severe cases of TSC involving multiple organs (heart, lungs, kidneys, brain). In the case of predominantly dermatological forms, topical application is always preferable.
A 0.05 or 0.1% sirolimus vaseline is sufficient for this.

Sirolimus is a highly potent drug with a strong immunosuppressive effect and therefore requires appropriate occupational safety.

mTOR inhibitor rapamycin (sirolimus) as a treatment option for tuberous sclerosis


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