Multi-phasic eGFR trajectory during follow up and long-term graft failure after kidney transplantation.

BACKGROUND: The prevailing assumption is that following kidney transplantation the pattern of kidney function decline is consistent. Nevertheless, numerous factors leading to graft loss may emerge, altering the trajectory of kidney function. In this study, we aim to assess alterations in estimated glomerular filtration rate (eGFR) trajectory over an extended period of follow-up and examine its correlation with graft survival. METHODS: We calculated eGFR using all creatinine values available from 1-year post transplantation to the end of follow-up. For pattern analysis, we used a piecewise linear model. RESULTS: Nine hundred eighty-eight patients were included in the study. After a median follow-up of 5.2 years, 297 (30.1%) patients had a multi-phasic eGFR trajectory. Change in eGFR trajectory was associated with increased risk for graft failure (HR 7.15, 95% CI 5.17-9.89, p < .001), longer follow-up time, younger age, longer cold ischemia time, high prevalence of acute rejection, longer hospitalization and a lower initial eGFR. Of the 988 patients included in the study, 494 (50.0%) had a mono-phasic stable trajectory, 197 (19.9%) had a mono-phasic decreasing trajectory, 184 (18.6%) had bi-phasic decreasing trajectory (initial stability and then decline, 46(4.7%) had a bi-phasic stabilized (initial decline and then stabilization) and 67(6.8%) had a more complex trajectory (tri-phasic). Out of the total 144 patients who experienced graft loss, the predominant pattern was a bi-phasic decline characterized by a bi-linear trajectory (66 events, 45.8%). CONCLUSIONS: Changes in eGFR trajectory during long-term follow-up can serve as a valuable tool for assessing the underlying mechanisms contributing to graft loss.

Absence of hemoglobin increase is associated with reduced graft survival after kidney transplantation.

BACKGROUND: Anemia is prevalent following kidney transplantation and is associated with reduced graft survival. The association between temporal changes in hemoglobin (Hb) level at the early post-transplant period and graft survival is unknown. PATIENTS AND METHODS: The study cohort included consecutive patients included in a single center transplantation registry between January 2002 and December 2016. Temporal changes in Hb values during the first 90 days after the transplantation were evaluated by piecewise linear regression model. Significant Hb increase rate was defined as an increase of .5 gram/deciliter/month. Patients were divided into groups according to the presence of significant Hb increase. The primary outcome was death-censored graft failure. RESULTS: Of 946 patients included in the study cohort, 831 (87.8%) had at least one interval of Hb increase, and 115 (12.2%) had no Hb increase. The absence of Hb increase was associated with an elevated risk of death censored graft failure by univariate (HR 2.9, 95% CI 1.88-4.49, P < .001) and multivariate (HR 2.47, 95% CI 1.48-4.12, P = .001) analyses. The timing and rate of Hb increase had no association with the main outcome. CONCLUSIONS: Lack of Hb increase during the early post-transplant period is associated with an increased risk of graft loss.

Meshing complex macro-scale objects into self-assembling bricks.

Self-assembly provides an information-economical route to the fabrication of objects at virtually all scales. However, there is no known algorithm to program self-assembly in macro-scale, solid, complex 3D objects. Here such an algorithm is described, which is inspired by the molecular assembly of DNA, and based on bricks designed by tetrahedral meshing of arbitrary objects. Assembly rules are encoded by topographic cues imprinted on brick faces while attraction between bricks is provided by embedded magnets. The bricks can then be mixed in a container and agitated, leading to properly assembled objects at high yields and zero errors. The system and its assembly dynamics were characterized by video and audio analysis, enabling the precise time- and space-resolved characterization of its performance and accuracy. Improved designs inspired by our system could lead to successful implementation of self-assembly at the macro-scale, allowing rapid, on-demand fabrication of objects without the need for assembly lines.