A team of scientists from the Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, have found that a combination of vitamin A and vitamin D3 could be used to treat visceral leishmaniasis or kala azar.
The parasite causing kala azar mainly affects liver, spleen and bone marrow. There are only a few drugs available for treatment and those available are expensive, causing toxicity and need parenteral administration over long periods. However, emerging multi-drug resistant strains are making treatment more complex.
Kala azar, a disease that is endemic to a few districts in West Bengal, Bihar, Jharkhand and eastern Uttar Pradesh, in India, is caused by leishmania donovani parasite, harboured by an insect called the sandfly. Kala azar is the second-largest parasitic killer after malaria worldwide, causing an estimated 2 lakh new infections each year. Since humans are the only hosts of the parasite, early detection and treatment makes elimination achievable.
India accounts for half of the new infections, with the disease flourishing in 54 districts – 33 in Bihar, 4 in Jharkhand, 11 in West Bengal and 6 in eastern Uttar Pradesh. Researchers at PGIMER chose to study effects of the combination of the two vitamins since in recent times several studies have shown that vitamin molecules can also play a role as antidotes against infectious diseases.
Specifically, vitamin A has been shown to prevent several ailments like diarrhea and respiratory diseases while vitamin D3 has demonstrated therapeutic effects on various organs and tissues. Scientists also looked at the viability of vitamin A in combination with chenodeoxycholic acid – a bile acid – which has been shown to prevent the formation of gallstone.
The two combinations tested on mice revealed that those administered with the vitamin A -vitamin D3 combination reduced the impact of kala azar by as much as 81 per cent in liver and 75 per cent in the spleen as compared to the control group. The parasite load got reduced in mice given vitamin A-chenodeoxycholic acid also but the effect was not as good. The virus load in this group came down by only 45 per cent in liver and 47 per cent in spleen.
The research team then probed the immune-modulatory response of the two combos by inducing kala azar infection in mice that had been treated with them. They found that the mice that were treated with vitamin A – vitamin D3 combo developed significant inhibition against the disease on the 21st day after the drug was administered. The mice treated with vitamin A – chenodeoxycholic acid combo did so on the 28th day. This indicates that the two combos could possibly be used as an adjunct to build immunity against the disease in people living in kala azar endemic areas. This could also be of use in treatment of the virus not responding to commonly used drugs.
“We are excited with our findings. However, we need to conduct further studies before we can go for clinical trials. A main advantage of the combos over the existing treatment could be that they may be less expensive and be amenable to be administered orally,” said Dr Rakesh Sehgal, leader of the research team.
The study team included Dr Venkateswara Reddy Gogulamudi, Dr Mohan Lal Dubey, Dr Ramesh Kandimalla, Dr Deepak Kaul (PGIMER) and Dr Donfack Jean Hubert (University of Dschang, Cameroon). The study results have been published in journal Scientific Reports.
(With inputs from India Science Wire)