The bridge between transplantation and regenerative medicine: Beginning a new Banff classification of tissue engineering pathology

Abstract

The science of regenerative medicine is arguably older than transplantation—the first major textbook was published in 1901—and a major regenerative medicine meeting took place in 1988, three years before the first Banff transplant pathology meeting. However, the subject of regenerative medicine/tissue engineering pathology has never received focused attention. Defining and classifying tissue engineering pathology is long overdue. In the next decades, the field of transplantation will enlarge at least tenfold, through a hybrid of tissue engineering combined with existing approaches to lessening the organ shortage. Gradually, transplantation pathologists will become tissue‐(re‐) engineering pathologists with enhanced skill sets to address concerns involving the use of bioengineered organs. We outline ways of categorizing abnormalities in tissue‐engineered organs through traditional light microscopy or other modalities including biomarkers. We propose creating a new Banff classification of tissue engineering pathology to standardize and assess de novo bioengineered solid organs transplantable success in vivo. We recommend constructing a framework for a classification of tissue engineering pathology now with interdisciplinary consensus discussions to further develop and finalize the classification at future Banff Transplant Pathology meetings, in collaboration with the human cell atlas project. A possible nosology of pathologic abnormalities in tissue‐engineered organs is suggested.

Diagnosis of renal transplant rejection: Banff classification and beyond

“…Lastly, with recent advances in bioengineered organs, we may also need to implement strategies to deal with abnormalities in bioengineered organs. Recently, Solez et al [67] proposed the construction of a framework for the classification of tissue engineering pathology at future Banff Transplant Pathology meetings, in collaboration with the Human Cell Atlas project [68].…”

The Human Cell Atlas Project by the numbers: Relationship to the Banff Classification

“…To the Editor Two recent AJT articles refer to the "step change" that the Human Cell Atlas Project (HCAP) will bring about in transplantation. 1,2 Many readers will want to know how big that step will be. On the one hand, HCAP reports are appearing in the top journals, and there are videos and articles about it widely available on social media, with predictions of a 10-to-100 000-fold increase in known cell types and claims such Pathology, as pointed out in a recent personal viewpoint paper.…”

“…On the one hand, HCAP reports are appearing in the top journals, and there are videos and articles about it widely available on social media, with predictions of a 10-to-100 000-fold increase in known cell types and claims such Pathology, as pointed out in a recent personal viewpoint paper. 2 As for the question of how many cells the project plans to characterize, the HCAP White Paper 5,6 is clear that the intention is to profile 30-100 million cells from healthy controls of both sexes in the first draft of the project and then incorporate the lessons learned from that into creation of a comprehensive atlas of at least 10 billion cells, covering all tissues, organs, and systems. The guiding principle determining how many cells will be analyzed is "Given a tissue with N discrete cell subsets, the rarest of which is present at proportion P, how many cells k need to be sampled such that at least n cells are recovered in each subset with confidence level C?"…”

“…The new Banff Classification of Tissue Engineering Pathology was first suggested in 2011, and concrete plans to make it happen have been in place since 2017, with the aim to have it completely finalized by 2025 2. HCAP is an integral part of the new Banff Classification of Tissue Engineering Pathology.…”

A 2018 Reference Guide to the Banff Classification of Renal Allograft Pathology: Erratum

“…Through regenerative medicine and tissue engineering and other optimizing initiatives we will eventually be able to provide organs to everyone in need. For this, we will need a new Banff Classification of Tissue Engineering Pathology 24,25 FIGURE 20. Banff Classification Diagnostic Category 6 (other).…”