Thursday, February 12, 2009

Injectable Tan?

When I was at the University of Arizona there were various news stories about a so-called "Barbie" drug that stimulated tanning, libido, and weight loss... great right? Perhaps. There were actually two drugs developed at the University of Arizona called Melanotan I and II which are analogs of the naturally occurring hormone called alpha-MSH, or melanocyte stimulating hormone. These drugs and the hormone stimulate (among other things) increased melanin production by melanocytes in the skin, thus leading to increased pigmentation or tanning. When your skin cells or keratinocytes are bombarded with UV light, they release alpha-MSH or closely related peptides that then trigger natural tanning as a protection to UV exposure and damage (see link).

The possibility of an injectable or drug-induced tan is quickly becoming a reality in Europe, Australia, and now even the United States. Clinuvel Pharmaceuticals is performing late stage clinical trials with afamelanotide (or melanotan I) as a photoprotective drug that induces skin pigmentation... tanning. Afamelanotide is being promoted as a photoprotective product to treat several skin disorders that cause photosensitivity, while the drug's use in cosmetic tanning is being downplayed by the company. However, once a drug is eventually approved by agencies like the FDA then doctors are free to prescribe them for "off-label" use which would seemingly include cosmetic tanning. You can only imagine how popular that would be, right? Some concerns exist that melanotan could possibly cause melanocytes to become cancerous (e.g., melanoma). However, safety concerns like these would obviously need to be addressed before the drug is approved for use in people. Note: the potential use of melanotan I and II for sexual dysfunction seems to have been halted due to safety issues and of course the availability of effective drugs like Viagra and Cialis. Melanotan uses in obesity therapy and weight loss seem to be in very early stages at best. See Palatin Technologies for these uses of melanotan.

Read a recent Wire blog entry about melanotan and Clinuvel here at this link.

~ ~ BIO26 ~ ~

Tuesday, February 10, 2009

Mitral Valve Repair in the news...

This news story/release caught my attention since it involves repair of the mitral valve (aka, the bicuspid or left atrioventricular valve). The repair is interesting since it does not require open heart surgery which might normally be used to repair or replace a leaky mitral valve. Watch the video below from YouTube and follow this link to the news story video if you are interested:

The device is called MitraClip... pretty catchy. Based on what I have read on the internet, the device accomplishes a similar result without opening the chest or arresting the heart. Some surgeons do a similar mitral repair that requires opening the chest and use of a cardiopulmonary bypass machine during the surgery to do the job of the heart and lungs during the 2-3 hour surgery. In contrast, the MitraClip procedure is done via access from the femoral vein and so the patients heart is still beating and the chest is not opened. The cusps or leaflets of the mitral valve are clipped together at the center to reduce the regurgitation or backflow of blood from the left ventricle into the left atrium during ventricular systole.

You might try to figure out how they can access the left atrium via the femoral vein? The LA and systemic veins don't exactly connect up unless you travel through the pulmonary circulations. Not really possible right? Well, turns out the surgeons or interventional cardiologists use whats called a transseptal route to the left atrium. A guide catheter is threaded into the inferior vena cava from the femoral vein up to the right atrium. Then they gain access to the left atrium by simply puncturing through the interatrial septum. Thus the go from the RA to the LA through the heart wall between the chambers... called the septum. Some studies even seem to mention using the fossa ovalis as a landmark or site for the transseptal puncturing.

~ ~ BIO26 ~ ~