Organ transplant rejection may not be permanent

Rejection of transplanted organs in hosts that were previously tolerant may not be permanent, report scientists from the University of Chicago. Using a mouse model of cardiac transplantation, they found that immune tolerance can spontaneously recover after an infection-triggered rejection event, and that hosts can accept subsequent transplants as soon as a week after. This process depends on regulatory T-cells, a component of the immune system that acts as a "brake" for other immune cells. The findings, published online in Nature Communications on July 7, support inducing immune tolerance as a viable strategy to achieve life-long transplant survival.

"Transplantation tolerance appears to be a resilient and persistent state, even though it can be transiently overcome," said Anita Chong, PhD, professor of transplantation surgery at the University of Chicago and co-senior author of the study. "Our results change the paradigm that immune memory of a transplant rejection is invariably permanent."

To prevent transplant rejection in patients with end-stage organ failure, a lifelong regimen of immune-suppressing drugs is almost always required. While difficult to achieve, immune tolerance - in which a transplanted organ is accepted without long-term immunosuppression - can be induced in some patients. However, rejection can still be triggered by events such as bacterial infection, even after long periods of tolerance. It has been assumed that the immune system remembers rejection and prevents future transplants from being tolerated.

Successful Test of Artificial Pancreas System, Hypoglycemia Hyperglycemia Minimizer (HHM) System For Type 1 Diabetes

In response to high levels of glucose in the blood, the insulin-producing cells in the pancreas secrete the hormone insulin. Type I diabetes occurs when these cells are destroyed by the body’s own immune system.

Diabetes is a life long disease in which the body has difficulty in maintaining the high levels of glucose (sugar) in the blood. Insulin is needed by the body to regulate glucose levels. In diabetes, there is too little insulin or the body is resisting the insulin, or both.

There are two types of diabetes, Type 1 and Type 2 diabetes. In type 1 diabetes, the cells that produce the insulin (beta cells) produce little or no insulin. With type 2 diabetes, the insulin produced is rejected by the body.

In type 1 diabetes, the body mistakenly identifies the beta cells located in the pancreas as harmful and start attacking it. Because of this, type 1 is identified as an autoimmune disorder. This kind of disorder is hereditary and can be passed down through families.

Positive results from first human clinical trials of a first-generation artificial pancreas system

Results from the first feasibility study of an advanced first-generation artificial pancreas system were presented today at the 72nd Annual American Diabetes Association Meeting in Philadelphia. Findings from the study indicated that the Hypoglycemia-Hyperglycemia Minimizer (HHM) System was able to automatically predict a rise and fall in blood glucose and correspondingly increase and/or decrease insulin delivery safely. The HHM System included a continuous, subcutaneous insulin pump, a continuous glucose monitor (CGM) and special software used to predict changes in blood glucose. The study was conducted by Animas Corporation in collaboration with JDRF as part of an ongoing partnership to advance the development of a closed-loop artificial pancreas system for patients with Type 1 diabetes.

"The successful completion of this study using the HHM System in a human clinical trial setting is a significant step forward in the development of an advanced first-generation artificial pancreas system," said Dr. Henry Anhalt, Animas Chief Medical Officer and Medical Director of the Artificial Pancreas Program. "It lays the foundation for subsequent clinical trials, bringing us one step closer to making the dream of an artificial pancreas a reality for millions of people living with Type 1 diabetes."

MIT News: Nanoparticle Coating Help Hip And Knee Implant Last Longer

Hydroxyapatite nanoparticles are incorporated
 into multilayer coatings for faster bone tissue growth.

CAMBRIDGE, Mass. -- Every year, more than a million Americans receive an artificial hip or knee prosthesis. Such implants are designed to last many years, but in about 17 percent of patients who receive a total joint replacement, the implant eventually loosens and has to be replaced early, which can cause dangerous complications for elderly patients.

To help minimize these burdensome operations, a team of MIT chemical engineers has developed a new coating for implants that could help them better adhere to the patient’s bone, preventing premature failure.

“This would allow the implant to last much longer, to its natural lifetime, with lower risk of failure or infection,” says Paula Hammond, the David H. Koch Professor in Engineering at MIT and senior author of a paper on the work appearing in the journal Advanced Materials.

The coating, which induces the body’s own cells to produce bone that fixes the implant in place, could also be used to help heal fractures and to improve dental implants, according to Hammond and lead author Nisarg Shah, a graduate student in Hammond’s lab.

An alternative to bone cement

Artificial hips consist of a metal ball on a stem, connecting the pelvis and femur. The ball rotates within a plastic cup attached to the inside of the hip socket. Similarly, artificial knees consist of plates and a stem that enable movement of the femur and tibia. To secure the implant, surgeons use bone cement, a polymer that resembles glass when hardened. In some cases, this cement ends up cracking and the implant detaches from the bone, causing chronic pain and loss of mobility for the patient.

New Organ Transplant Method Without Requiring Anti-Rejection Medicine

Some doctors look at organ transplantation without the use of drugs as the "Holy Grail" of organ transplantation. For a long time, organ recipients take powerful and expensive anti-rejection medication to prevent organ damage and infection for the rest of their lives. These medication comes with a cost. Side effects with prolonged use of these anti-rejection medicine include high blood pressure, diabetes, infection, heart disease and cancer.

Two years ago, Stanford Hospital successfully matched up a patients who were immunologically identical and transplanted a kidney without the use of anti-rejection medication. This was done by introducing the donor's blood stem cells into the system.

So far, the procedure only works for sibling donors and recipients.

Now, scientists released a first-of-its-kind study where donor, recipient are not related or immunologically matched

New ongoing research published today in the journal Science Translational Medicine suggests organ transplant recipients may not require anti-rejection medication in the future thanks to the power of stem cells, which may prove to be able to be manipulated in mismatched kidney donor and recipient pairs to allow for successful transplantation without immunosuppressive drugs. Northwestern Medicine® and University of Louisville researchers are partnering on a clinical trial to study the use of donor stem cell infusions that have been specially engineered to "trick" the recipients' immune system into thinking the donated organ is part of the patient's natural self, thus gradually eliminating or reducing the need for anti-rejection medication.

"The preliminary results from this ongoing study are exciting and may have a major impact on organ transplantation in the future," said Joseph Leventhal, MD, PhD, transplant surgeon at Northwestern Memorial Hospital and associate professor of surgery and director of kidney and pancreas transplantation at Northwestern University Feinberg School of Medicine. "With refinement, this approach may prove to be applicable to the majority of patients receiving the full spectrum of solid organ transplants."