Rheumatic Heart Disease Research

Tragically, those most affected by RHD are young people

Rheumatic Heart Disease is considered a developing world disease, yet in New Zealand 600-800 people are diagnosed with it every year with about 150-200 people dying as a result of the disease. Tragically, those most affected by RHD are young people, and they are disproportionately Māori and Pasifika.
RHD begins as Rheumatic Fever or ‘strep throat’ which can be treated with penicillin. But repeated infections or if left untreated the strep throat can progress into Rheumatic Heart Disease. There is ongoing research into why rates of RHD are so high in Aotearoa New Zealand but we know that access to primary healthcare, poverty, poor quality, damp homes and overcrowding all contribute to the risk of disease. At Manaaki Manawa we are working on a number of projects to try to address this problem.

3D Heart Valve Project

RHD is an autoimmune disease that attacks the valves of the heart causing them to leak. People who develop RHD will require repeated surgeries throughout their lives and can expect a shortened life as a result. Most will require a heart valve replacement. At the moment most people receive a mechanical valve but there are two problems here; the first is the risk of rejection by your body and the second is that the valve does not grow with your heart. Remembering that most victims of RHD are young when they are first diagnosed, they will need repeated open heart surgeries to replace their valves throughout their lives as their heart grows.

At Manaaki Manawa we are working on several projects to improve heart valve replacements but the most compelling is the 3D modelling project. Dr Olaf Diegel has the first 3D printer in Aotearoa that can print in hydrogel. Using this hydrogel we are working on printing growth matrices and scaffolds which would be ideal for growing personalised body parts, including heart valves. It is a truly interdisciplinary project at the intersection of engineering and medicine.

The benefits of being able to grow these valves using 3D growth scaffolds cannot be overstated. The recipient would only ever need one operation. The recipients would have a painless skin biopsy and we would then turn those skin cells into stem cells and reprogramme the stem cells to be heart valve cells. The recipient would have an MRI and the scaffold would be made to fit perfectly into their heart and because it is an autograft it would grow with the recipient and not be rejected.

Needle Free Injector

The University of Auckland have already developed a needle free jet injector which has the capacity to deliver antibiotics and is being used to deliver insulin to diabetics. It is a remarkable invention that may ultimately mean we don’t have to use needles at all. This has a number of benefits. Obviously needles are unpleasant so it will increase compliance because the injection system will be better tolerated from a psychological and physical point of view. The injection itself may be pain free.

We see real potential for this needle free injector to be used to deliver penicillin for rheumatic fever patients but penicillin is more viscous than the drugs currently being administered and the injectate needs to go deeper into the body (muscle) and at a greater volume than the current drugs that have so far been tested.

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