It might sound unbelievable, but the rabies virus has been put to rather ‘useful’ use. The rabies virus, (like any typical viruses that affect the Central Nervous System (CNS)) has the ability to penetrate even through the strongest barriers that the brain secures itself with. The virus usually penetrates through any tumour or clot that the blood-brain barrier has, and affects the respective systems and functions. Only this time, its mechanics have been emulated for a rather path breaking discovery. And it’s Manjunathan N. Swamy (and his team) at Harvard Medical School’s Immune Disease Institute who is to be thanked. The rather exhaustive article by Rakesh K. Jain, a renowned scientist, in the January edition of Scientific American–India traces and looks closely at the problems of what is scientifically termed ‘Vascular Endothelial Growth Factor’ (VEGF), especially with respect to abnormal vasculature inherent in many diseases. Millions of patients who are afflicted with any condition that affects the CNS are sometimes plagued by a rather ubiquitous problem. For the drugs (which hardly ever are 100% effective) to even reach the site of dysfunction becomes a problem with the formation of tumours. Tumours, which are either malignant or benign, are formed by cells reproducing in a hyper-fashion and very quickly so. Once a tumour is formed, it more often than not becomes enmeshed with the blood vessels around it.
VEGF, Jain writes, promotes proliferation and strengthening of the endothelial cells that line the inner cell walls of the blood vessel. In tumours, however, the balance between VEGF and molecules that inhibit blood vessel growth is thrown off, leading to a highly abnormal growth in blood vessels. This makes the procedure of surgical removal of any tumour rather risky, especially in the brain, where exists the added risk of injury to a neuron. Jain explains that the blood vessels in a tumour are sometimes wont to branch rather “erratically”, are irregular in breadth and highly chaotic in their structure. All this, he asserts, “contributes to irregular blood flow”. The tumours then produce an environment of hypoxia (extremely low levels of oxygen) and thus render any radiation or chemotherapy ineffective by becoming blockades or barriers.
The drug that the Harvard team has come up with, by the way of its penetrating capabilities, can be used towards “normalizing” of the affected dysfunctional blood vessel. Disguised as a virus, the drug is released into the blood-brain barrier and helps make the cell wall more porous. This discovery may perhaps not be at the focus of media attention, since it is not a cure by itself and is only in its experimental stages. However, it certainly can be a way to the cure, another step that leads us towards perhaps one of the biggest mysteries of the medical world; and hence takes its place in the hall of fame as an important and potentially miraculous achievement.
All quotes cited to: ScientificAmerican-India; Jan 2008. Volume: 3 No: 1, pages 28-46.