New immunosuppressive drugs in heart transplantation

Novel Immunosuppression in Solid Organ Transplantation

Solid organ transplantation and survival has improved tremendously in the last few decades, much of the success has been attributed to the advancements in immunosuppression. While steroids are being replaced and much of the immunosuppressive strategies focus on steroid free regimens, novel agents have introduced in the induction, maintenance, and treatment of acute rejection phase. MTOR inhibitors have helped with the renal sparing side effect from the calcineurin inhibitors, newer agents such as rituximab have decreased the incidence of donor-specific antibodies which led to decreased incidence of acute rejection reactions. In this chapter we discuss the newer therapies directed specifically for solid organ transplantation.

Micro RNA-98 suppresses interleukin-10 in peripheral B cells in patient post-cardio transplantation

The immune tolerance to the transplant heart survival is critical. Regulatory B cells are one of the major immune regulatory cell populations in the immune tolerance. Micro RNAs (miR) can regulate the activities of immune cells, such as the expression of interleukin (IL)-10 by B cells. This study tests a hypothesis that micro RNA (miR)-98 plays a role in the regulation of interleukin (IL)-10 expression in B cells (B10 cell) after heart transplantation. In this study, the peripheral blood samples were collected from patients before and after heart transplantation. The expression of miR-98 and IL-10 in B cells was assessed by real time RT-PCR. An allograft heart transplantation mouse model was developed. We observed that after heart transplantation, the frequency of peripheral B10 cell and the IL-10 mRNA levels in peripheral B cells were significantly decreased, the levels of miR-98 were increased in peripheral B cells and the serum levels of cortisol were increased in the patients. Treating naive B cells with cortisol in the culture suppressed the expression of IL-10 in B cells, which was abolished by knocking down the miR-98 gene. Administration with anti-miR-98, or cortisol inhibitor, or adoptive transfer with B10 cells, significantly enhanced the survival rate and time of mice received allograft heart transplantation. In conclusion, the enhancement of serum cortisol affects the immune tolerant feature of B cells, which can be attenuated by anti-miR-98-carrying liposomes.

Functional diversity and pharmacological profiles of the FKBPs and their complexes with small natural ligands

From 5 to 12 FK506-binding proteins (FKBPs) are encoded in the genomes of disparate marine organisms, which appeared at the dawn of evolutionary events giving rise to primordial multicellular organisms with elaborated internal body plan. Fifteen FKBPs, several FKBP-like proteins and some splicing variants of them are expressed in humans. Human FKBP12 and some of its paralogues bind to different macrocyclic antibiotics such as FK506 or rapamycin and their derivatives. FKBP12/(macrocyclic antibiotic) complexes induce diverse pharmacological activities such as immunosuppression in humans, anticancerous actions and as sustainers of quiescence in certain organisms. Since the FKBPs bind to various assemblies of proteins and other intracellular components, their complexes with the immunosuppressive drugs may differentially perturb miscellaneous cellular functions. Sequence-structure relationships and pharmacological profiles of diverse FKBPs and their involvement in crucial intracellular signalization pathways and modulation of cryptic intercellular communication networks were discussed.

Long-term follow-up after staged reconstruction or transplantation for patients with functionally univentricular heart

As recently as 35 years ago, children born with a functionally single ventricle were destined to a lifetime of multiple palliative operations, and disrupted growth and development. Physical signs of their cardiac disease were evidenced by chronic hypoxemia, polycythemia, clubbing, small stature, and severely reduced exercise ability. A normal lifestyle, with typical landmarks such as uninterrupted adolescence and potential childbearing, was unlikely. The successful application of right heart bypass by Fontan and Kreutzer in the early 1970s heralded an era of multiple medical and surgical breakthroughs that have systematically improved the quality of life and long-term outlook for these children.

Challenges in heart transplantation: now and the future

Little more than 30 years after the first human operation, heart transplantation continues to be the gold standard treatment for heart failure disease. During these years, surgical procedures and immunosuppressive treatment have improved and the survival rate continues to improve despite transplanting older and sicker patients. However, there are still many challenges that we are currently facing. Regarding organ shortage, donor heart acceptance criteria have been reconsidered. Better donor management could increase the organ pool, maximizing the use of hearts recovered from cadaveric donors. Concerning organ allocation, recent improvements in medical treatment could restrict transplantation procedures to the patients at greatest risk of dying. Controlling allograft rejection, vasculopathy, and malignancies are current challenges. Cyclosporine, azathioprine, and corticosteroids have been the mainstay of immunosuppression, but carry severe adverse systemic effects. Today, new pharmacologic agents have become available and hold the possibility to improve the length and quality of recipient life.