Genome-wide Disease Screening in Early Human Embryos with Primary Template-Directed Amplification

Current preimplantation genetic testing (PGT) enables the selection of embryos based on fetal aneuploidy or the presence a small number of preselected disease-associated variants. Here we present a new approach that takes advantage of the improved genome coverage and uniformity of primary template-directed amplification (PTA) to call most early embryo genetic variants accurately and reproducibly from a preimplantation biopsy. With this approach, we identified clonal and mosaic chromosomal aneuploidy, de novo mitochondrial variants, and variants predicted to cause mendelian and non-mendelian diseases. In addition, we utilized the genome-wide information to compute polygenic risk scores for common diseases. Although numerous computational, interpretive, and ethical challenges, this approach establishes the technical feasibility of screening for and preventing numerous debilitating inherited diseases.

MO089HISTOMORPHOMETRIC ANALYSIS OF GLOMERULI AND CAPILLARIES DENSITY IN THE INTERSTITIUM IN PREIMPLANTATION NEEDLE BIOPSIES OF PAIRED KIDNEYS HARVESTED FROM ADULT CADAVERIC DONORS

Background and Aims Preimplantation needle biopsy of kidney allows more precise interpretation of subsequent kidney biopsies performed after transplantation and potentially also may predict kidney graft survival. It is unknown, whether it is justified to perform the biopsy of one kidney only and then to transmit obtained results also to the second kidney or biopsies of both kidneys are mandatory. The aim of the study was to assess differences regarding glomerular volume, glomerular density and capillary density in the interstitium of both kidneys harvested from the same deceased donor. Method The study involved 40 pairs of kidneys (all together 80 kidneys) in which preimplantation kidney biopsies were performed. Kidneys were harvested from 40 deceased donors (17 females and 23 males; mean age 42.3 [37.6-47.0] years old) died because of intracranial haemorrhage (17 donors) or cerebral trauma due to accident (23 donors). Histomorphometric analysis was performed using “Olympus BX51” microscope (Olympus, Tokyo, Japan) coupled with “Olympus BX50” camera and the “cellSens Standard” software (Olympus, Tokyo, Japan). Weibel-Gomez formula was adapted to calculate glomerular volume. Results No significant differences were found between mean kidneys length [115.8 (112.4-119.1) vs.115.5 (112.5-118.5) mm], glomerular volume [2.59 (2.24-2.93) vs 2.49 (2.15-2.84) μm3 x106 ], glomerular density [3.43 (3.07-3.80) vs 3.24 (2.87-3.61) n/mm2] and interstitial capillaries density [233.58 (211.26) vs 217.80 (199.45-236.47) n/mm2] of both kidneys harvested from the same deceased donor. Conclusions 1. Both kidneys harvested from the same deceased donor did not differ significantly in kidney length, glomerular volume, glomerular density and capillary density. 2. Our results justify to preimplantation biopsy of only one kidney and the results from the histomorphometric analysis may be used in the future also for assessment of the second kidney.

Preimplantation Biopsy Predicts Delayed Graft Function, Glomerular Filtration Rate and Long-Term Graft Survival of Transplanted Kidneys

Background The predictive value of preimplantation biopsies for long-term graft function is often limited by conflicting results. The aim of this study was to evaluate the influence of time-zero graft biopsy histological scores on early and late graft function, graft survival and patient survival, at different time points. Methods We retrospectively analyzed 284 preimplantation biopsies at a single center, in a cohort of recipients with grafts from live and deceased donors (standard and nonstandard), and their impact in posttransplant renal function after a mean follow-up of 7 years (range 1–16). Implantation biopsy score (IBS), a combination score derived from 4 histopathological aspects, was determined from each sample. The correlation with incidence of delayed graft function (DGF), creatinine clearance (1st, 3rd and 5th posttransplant year) and graft and patient survival at 1 and 5 years were evaluated. Results Preimplantation biopsies provided somewhat of a prognostic index of early function and outcome of the transplanted kidney in the short and long term. In the immediate posttransplantation period, the degree of arteriolosclerosis and interstitial fibrosis correlated better with the presence of DGF. IBS values between 4 and 6 were predictive of worst renal function at 1st and 3rd years posttransplant and 5-year graft survival. The most important histological finding, in effectively transplanted grafts, was the grade of interstitial fibrosis. Patient survival was not influenced by IBS. Conclusions Higher preimplantation biopsy scores predicted an increased risk of early graft losses, especially primary nonfunction. Graft survival (at 1st and 5th years after transplant) but not patient survival was predicted by IBS.