Transplantation Technologies & Research

Renal transplant pathology is a complex and rapidly evolving field of surgical pathology and the pathologic interpretation of renal allograft biopsy pose significant challenges and opportunities to the renal transplant pathologists. Both allo-immune and non-immune factors often interplay in causing damage to the kidney allograft at different time intervals post-transplantation. An accurate identification of these etiologic factors is essential for the optimal management and better long-term outcome of the renal transplant patients and the biopsy plays a pivotal role in this process. The Banff classification was introduced as an international, consensus-based working formulation to harmonize the reporting of pathological lesions seen on renal allograft biopsies. The first meeting of the Banff group took place in 1991 and the first detailed publication on the classification appeared in 1993. Subsequent meetings have been held regularly every two years with regular updates, additions and revisions of the original classification. The latest meeting was held in Brazil this year (2013) and its detailed reporting is still due.

This editorial attempts to summarize the main changes that have taken place in the interpretation of renal allograft biopsy pathology and the Banff classification over the last two decades. The main focus of the paper will be on the evolution of the morphological and immunohistochemical changes, as these are still the mainstay of the Banff classification. The standardization and incorporation of the formal morphometric and molecular data into the Banff classification for practical use is still a challenge for the future.

The main interest in human mesenchymal stromal cells (hMSCs) is correlated with their ability to suppress the proliferation of immune cells and to regulate the transplantation rejection. The mechanisms at the basis of MSCs activity need cell-cell interaction and the expression of molecules induced by the micro-environment. The inhibitory functions of MSCs involve several molecules as hepatocyte growth factor, transforming growth factor-beta (TGF-beta), interleukin-10 and -2 (IL-10, IL-2), tumour necrosis factor-alpha (TNF-alpha), prostaglandin E2 (PGE2), indoleamine 2,3-dioxygenase (IDO), and HLA-G antigens. A large consesus has been obtained on the immune-modulatory role of HLA-G molecules produced by hMSCs.

Stem cells are highly specialized biological cells that have the potential to differentiate and regenerate various cells and tissue types. Stem cell research was first initiated way back in 80’s due to the discovery of pluripotent embryonic stem cells. However, embryonic stem cells utilization spurred controversy which encouraged scientists to find an alternative for the substitution for ESCs. Human Mesenchymal Stem Cell (MSC), a type of an adult stem cell, exhibits many of the properties as that of embryonic stem cells such as pluripotency, immunomodulatory etc. These adult stromal cells are multipotent and non-hematopoietic in nature. MSCs have the potential to differentiate into diverse cell types including osteocytes, osteoblasts, adipocytes, chondrocytes, cardiomyocytes, neural cells and β-cells of islets. This differentiation property is exploited by many researchers in clinical and therapeutic applications of these cells against wide variety of diseases including osteoarticular diseases, neurodegenerative diseases, auto-immune diseases, cardiovascular diseases and in renal transplantation. Overall, this review summarises an importance of use of human Mesenchymal Stem cells (MSCs) for regenerative therapies for the cure of these major diseases in human.

While experimental studies on tracheal transplantation are numerous, these have failed to translate into wider clinical application due to various factors. This review discusses on the current techniques of processing, decontamination and storage of human tracheal allografts for clinical transplantation. We also present our lack of success in our attempt in tracheal allograft banking. With few allografts available for research, it is difficult to validate the effectiveness of various decontamination and preservation protocols. Some tissue banks adopt the use of controversial chemicals and irradiation for decontamination. While these methods may completely eliminate the risk of transmission of infectious diseases and micro-organisms, their effect on the integrity of the allograft and possible long-term side-effects to the patients remains unknown.

Lung transplantation unit from Hospital 12 de Octubre began its work in October 2008. In the last five years, 80 lung transplants have been performed with a hospital mortality rate of 6.5% and a five years survival of 79.7%. As a result of the need of obtaining a greater number of donors, and encouraged by the outpatient non heart beating donors program within our hospital, we considered the possibility of assessing these donors lung grafts. We have followed the methodology designed and set off with good results by other hospitals in the area of Madrid. Nevertheless some changes have been included such as Bithermical multiorgan preservation, where abdominal organs are preserved in normothermia and thoracic ones in hypothermia. However, this methodology has not been scientifically proven. We have reproduced in a laboratory lung function assessment manoeuvres of pulmonary grafts from non heart beating donors. Then we have compared the correlation with the lung function assessment before cardiac arrest, applying the procedure on 40 pigs. Outcomes are promising.