Miniature Surgeons

New therapies will combat blood 
diseases more effectively. Biplab Das reports  

Some day tiny robots measuring a hundred-thousandth of a human hair may roam freely in your bloodstream. Guided by tiny computers, these robots will repair faulty genes, seek out and destroy cancer cells, sparing healthy tissues with pinpoint precision. Last week, a national seminar-cum-workshop on 'Recent Developments in Haematology' discussed such medical scenarios from the future at the Medical College. The meet was organised by the Institute of Haematology and Transfusion Medicine (IHTM) at its auditorium. 

"Artificial red blood cells (RBCs) called Respirocytes - armed with tiny robots - are expected to increase the blood's capacity to carry oxygen 236-fold," said Dr. Rita Banerjee from the department of science and technology, Government of India. She believes this will not only replace lost RBCs caused by fatal blood disorders like leukaemia and thalassaemia, but will also deliver oxygen to gasping cells. 

Researchers have already made an extremely tiny structure called 'nanospring'. Once embedded inside our body, this 'nanospring' will send out radio signals through our skin as soon as it bumps into the first lethal protein molecule churned out by cancer cells. This will help diagnose life-threatening diseases like leukaemia and thalassaemia caused by genetic mutations at the earliest stage. Then there are nanorobots - not bigger than a billionth of a metre in width -, which will work as miniature surgeons. They will one day repair damaged cells, said Banerjee. "These tiny machines might replicate themselves or correct genetic deficiencies that underlie various blood diseases." But it will take at least a couple of decades before the tiny machines make their debut in medicine. 

Some tiny machines have already been launched to detect genetic blood disorders. Called DNA chips, these devices can pin down the culprit genes that bring about blood diseases like haemophilia. "Using these chips, a mutation to a gene called B94 has been detected," said Prof. D. J. Chattopadhyay from the biochemistry department, Calcutta University. 

The mutation he talked about leads to acute promyelocyte leukaemia, a type of blood cancer. "The chip can also help study the receptors (large protein molecules) attached to T cells, a type of white blood cell, which reveal the survival capacity of cancer cells," said Chattopadhyay. According to Prof. C. R. Maiti, director of Medical Education, government of West Bengal, use of diagnostic kits like the DNA chip can help cut down thalassaemia (highly prevalent in eastern India) through early detection of the culprit gene. 

Prof. Netai Bhattacharya from the Saha Institute of Nuclear Physics spoke on variations of DNA in rarer form of blood cancers. "One out 10 cases is caused by a mutation in a gene called p53, which codes for the p53 protein," he said. "Recently, researchers have identified a culprit gene called FLT3, which also causes blood cancer." According to Bhattacharya, this gene is the potential target for drug designers. 

Talking about recent advances in the assessment of thrombophilia in patients suffering from thrombosis (coagulation of blood in an organ or a blood vessel), Dr. Kanjaksha Ghosh, deputy director of Institute of Immunohaematology, Mumbai, said, "We have identified a patient afflicted with antithrombin III (AT III) deficiency." AT III is a molecule, which cripples thrombin, an enzyme that aids the formation of blood clots. In the absence of AT III, thrombin easily forms blood clots. "The AT III deficiency is a genetic disorder, which is passed down the family line," said Ghosh. "One out of 5000 people is afflicted with this disease." 

Prof. V. P. Choudhry of the All India Institute of Medical Sciences informed that at least 30 types of mutations have been found to cause thalassaemia in India. In thalassaemia, premature death of red blood cells builds up iron at an alarming rate. The excess iron accumulates in the brain, which has been observed through magnetic resonance imaging (MRI). 

To remove excess iron, a drug called deferiprone is now used. The new drug called ICL 670 removes iron more effectively while it protects the liver. Another technique known as 'wheat grass therapy' has been found to rev up the production of red blood cells, reducing the frequency of blood transfusions.

    June 14, 2004.