New way to deliver drugs in graft surgery

Immunosuppressants released only when and where needed
Last Updated 14 August 2014, 19:18 IST

The Institute for Stem Cell Biology and Regenerative Medicine (inStem) in Bangalore has collaborated with researchers in the USA and Switzerland in a study to devise a technique whereby the delivery of immunosuppressant drugs in graft transplant surgery can be done only when and where needed.  

The standard procedure in tissue graft transplants is the administration of immunosuppressants to weaken the immune system and prevent the body from rejecting the new tissue.

The new technique shown in the study uses a combination of hydrogel (a jello like material widely used in the medical field) and tacrolimus, an immunosuppressant drug.

When researchers injected this hydrogel loaded with tacrolimus in the skin of a rat after transplant surgery, it was found that hydrogel became active only when an inflammation or an immune response was detected from the site of the transplant. Subsequently, the immunosuppressant drug was delivered only within the transplanted graft.

Study findings

 The findings of the study conducted by researchers from inStem, India, Brigham and Women’s Hospital (BWH), USA and University Hospital of Bern, Switzerland was published in the medical journal, Science Translational Medicine on August 13, 2014.

In a press release issued by InStem, Praveen Kumar Vemula, PhD, Principal Investigator, inStem and co-corresponding study author, said, “Until now, delivering drugs for the treatment of autoimmune/inflammatory diseases has been extremely challenging due to unpredictable disease severity, thus traditional drug delivery systems fail. Hence, developing a novel approach where drug delivery systems release drugs in response to the disease severity is our vision.”

One-time injection

Pre-clinical results revealed that a one-time injection of the combo in the transplanted area prevented graft rejection for more than 100 days.

Jeff Karp, PhD, Division of Biomedical Engineering, BWH Department of Medicine, co-corresponding study author, said, “This new approach to delivering immunosuppressant therapy suggests that local delivery of the drug to the grafted tissue has benefits in reducing toxicity as well as markedly improving therapeutic outcomes and may lead to a paradigm shift in clinical immunosuppressive therapy in transplant surgery.”

“Continuous release of the drugs, irrespective of disease severity, that is a hallmark of existing drug delivery vehicles could be a thing of the past. Inflammation associated enzymes-directed drug release offers ‘judicious use of locally injected drug’ that extends the release for months while eliminating systemic toxicity,” says Robert Rieben, PhD, Head of Research at Reconstructive and Hand Surgery, Bern University Hospital and co-corresponding study author.

(Published 14 August 2014, 19:18 IST)

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