- New device that is implanted on the heart in a single surgical
procedure delivers multiple doses of localized therapy to heart following
a heart attack
- The device termed 'Therepi' could prevent progression from heart attack to heart failure
by promoting healing and improving heart function
- One of the most common complications following a heart attack is
heart failure as the heart tries to compensates for the non-functioning
and damaged heart tissue.
device augments healing of damaged heart and improves function by allowing
delivery of multiple doses of treatment in a non-invasive manner. The study
conducted by the team of scientists from MIT, Harvard
University, Royal College of Surgeons in Ireland, Trinity College Dublin,
Advanced Materials and BioEngineering Research (AMBER) Centre, and National
University of Ireland Galway appears in the journal Nature Biomedical
"After a heart attack
we could use this device to
deliver therapy to prevent a patient from getting heart failure," explains
Ellen Roche, co-first author of the study and assistant professor at MIT's
Department of Mechanical Engineering and MIT's Institute for Medical
Engineering and Science. "If the patient already has some degree of, heart failure
we can use the device to attenuate the
Details of How The 'Therepi'
- The device consists of a reservoir
that attaches directly to the damaged heart tissue by a one-time surgical
procedure. A refill line connects the reservoir to a port either on or
below the patient's skin through which treatment can be administered
either by the patient or a healthcare professional.
- The reservoir is fashioned out of a
gelatin-based polymer, and has a hemispherical shape with a flat bottom
that is attached to the damaged heart tissue. "The material we used
to construct the reservoir was crucial. We needed it to act like a sponge
so it could retain the therapy exactly where you need it
and that is difficult to accomplish since the heart is constantly moving
and squeezing," added Whyte.
- The reservoir holds tremendous
potential for drug delivery. The flat bottom consists of a
semipermeable membrane that can be
modified to permit more drug or larger molecules to pass into the heart
- The reservoir presents a wonderful
opportunity in administering stem cell therapies. It behaves like a cell
factory. The cells do not enter the heart but stay within the reservoir
where they secrete paracrine factors that then promote healing and repair
of the damaged heart tissue.
- The results showed that the device was
effective in improving cardiac function after a heart attack in a rat
model. In one group, multiple
doses of cells were administered
over a four week period to the damaged heart
and single dose or no treatment in another set of rats
by the team members.
- The team
assessed the hemodynamic changes in the heart tissue using
a pressure-volume catheter and also echocardiography was used to
compare the change in cardiac
- The rats
that received multiple dosages of cells via therapy were
found to have a better cardiac function when
compared to those who received only a single stem cell
injection or no treatment at all.
of Current Treatments in
Two of the available standard systems for
delivering therapies to prevent heart failure are inefficient and invasive.
- In the first method, drugs are
delivered systemically rather than locally to the site of the damage. The amount of drugs used therefore has to
be limited to avoid severe side effects and often only a small
fraction actually reaches the damaged heart tissue.
- In the other method,
an invasive procedure is employed
to directly inject therapies into the heart muscle. Should multiple doses
be needed, this would mean multiple invasive procedures.
'Therepi' addresses the
above issues by delivering localized, non-invasive treatment as many times as
required. Furthermore, the reservoir of the device can be implanted on the
heart in just a single surgical procedure.
Optimal Dose of Drug- Another Potential Use of Therepi Device
Since it enables multiple, localized
doses to be delivered, the Therepi device could be employed as a tool to
identify the exact optimal dosage for various conditions.
‘Therepi delivers multiple localized therapies to heart non-invasively via a port on or under the patient's skin and can be injected either by the patient himself or healthcare professional.’
Roche said that they are
hoping to use the device as a research tool to learn more about the optimal
drug loading regime.
- For the first time, scientists could
have an opportunity to closely
monitor multiple refills of localized therapies over a given period of
time to determine the best dosing intervals and dosage amount.
"As a pharmacist by training, I'm
really excited to start investigating what the best dose is, when is the best time to deliver after a heart
attack, and how many doses are needed to achieve the desired
therapeutic effect," adds Whyte.
Uses of Therepi
The device can be similarly used on other parts of the body to deliver treatments
optimizing the design and material used, the device can be modified for use in
various parts of the body for wide-ranging conditions.
"The device is really a platform
that can be tailored to different organ systems and different conditions.
It's just a great example of how intersectional research looking at both
devices and biological therapies can help us come up with new ways to treat
- Sustained release of targeted cardiac therapy with a replenishable implanted epicardial reservoir(https://www.nature.com/articles/s41551-018-0247-5)