The Clinical Impact of Anti-HLA Donor Specific Antibody Detection Through First Year Screening on Stable Kidney Transplant Recipients.

Anti-HLA Donor Specific Antibody (DSA) detection post kidney transplant has been associated with adverse outcomes, though the impact of early DSA screening on stable patients remain unclear. We analyzed impact of DSA detection through screening in 1st year stable patients (n = 736) on subsequent estimated glomerular filtration rate (eGFR), death censored graft survival (DCGS), and graft failure (graft loss including return to dialysis or re-transplant, patient death, or eGFR < 20 ml/min at last follow up). Patients were grouped using 1st year screening into DSA+ (Class I, II; n = 131) or DSA- (n = 605). DSA+ group were more DR mismatched (p = 0.02), more sensitized (cPRA ≥90%, p = 0.002), less Caucasian (p = 0.04), and had less pre-emptive (p = 0.04) and more deceased donor transplants (p = 0.03). DSA+ patients had similar eGFR (54.8 vs. 53.8 ml/min/1.73 m2, p = 0.56), DCGS (91% vs. 94%, p = 0.30), and graft failure free survival (76% vs. 82%, p = 0.11). DSA timing and type did not impact survival. Among those with a protocol biopsy (n = 515), DSA detected on 1st year screening was a predictor for graft failure on multivariate analysis (1.91, 95% CI 1.03-3.55, p = 0.04). Overall, early DSA detection in stable patients was an independent risk factor for graft failure, though only among those who underwent a protocol biopsy.

Donation after circulatory death is associated with increased fibrosis on 1-year post-transplant kidney allograft surveillance biopsy.

AIM: The use of kidneys donated after circulatory death (DCD) provides an invaluable expansion of the organ supply for transplantation. Here, we investigated the effect of DCD on fibrotic changes on 1 1-year post 1-transplant surveillance kidney allograft biopsy. METHODS: Recipients of a deceased donor kidney transplant between 2013 and 2017 at a single institution, who survived 1 year and underwent surveillance biopsy, were included in the analysis (n = 333: 87 DCD kidneys, 246 kidneys donated after brain death [DBD]). Banff scores for interstitial fibrosis and tubular atrophy were summed as IFTA and compared between the groups. RESULTS: DCD and DBD groups were comparable for baseline characteristics. Delayed graft function was 39% in DCD versus 19% in DBD, P = .0002. Patient and graft survival were comparable for DCD and DBD cohorts. IFTA scores were higher in DCD compared to DBD (2.43±..13 vs. 2.01±..08, P = .0054). On multivariate analysis, the odds of IFTA > 2 in the DCD group was 2.5× higher (95%CI: 1.354.63) than in the DBD group. Within the DCD group, kidneys with IFTA > 2 had inferior 5-year graft survival (P = .037). CONCLUSION: Compared to DBD kidneys, DCD kidneys developed a greater degree of fibrotic changes on 1-year post-transplant surveillance biopsy, which affected graft longevity within the DCD cohort.

Magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) is a viable alternative to liver biopsy for steatosis quantification in living liver donor transplantation.

This study aimed to investigate whether magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) can be a viable noninvasive alternative to liver biopsy for the quantification of living liver donor steatosis. Hepatic steatosis for 143 donors was graded by MRI-PDFF. Study endpoints included liver volume regeneration in donors, recipient outcomes including length of hospital stay, deaths, primary non-function (PNF), early allograft dysfunction (EAD), and small for size syndrome (SFSS). Correlation between MRI-PDFF determined donor steatosis and endpoints were analyzed. Donors had lower steatosis grade than non-donors. Donor remnant liver regenerated to an average of 82% of pre-donation volume by 101 ± 24 days with no complications. There was no correlation between percent liver regeneration and steatosis severity. Among recipients, 4 underwent redo-transplantation and 6 died, with no association with degree of steatosis. 52 recipients (36%) fulfilled criteria for EAD (driven by INR), with no difference in hepatic steatosis between groups. MRI-PDFF reliably predicted donor outcomes. Living donors with no or mild steatosis based on MRI-PDFF (ie, <20%) and meeting other criteria for donation can expect favorable post-surgical outcomes, including liver regeneration. Recipients had a low rate of death or retransplantation with no association between mild hepatic steatosis and EAD.

Epidemiology of end-stage renal failure among twins and diagnosis, management, and current outcomes of kidney transplantation between identical twins.

The aim of the study is to provide a comprehensive overview of identical twin kidney transplantation in the modern era. We provide epidemiologic trends in the US twin population from 1959 to 2000, current methods to identify zygosity, outcomes for identical twin transplants, and a comprehensive management strategy for identical twin kidney transplantation. By 2019, we project that 433 010 dizygotic and monozygotic twins will be alive and at risk for developing ESRF. Monozygosity between a donor-recipient pair can be confirmed by concordance in sex, blood type, and HLA antigen match with precision testing using 13/17 Short Tandem Repeat sequencing to a likelihood of nearly 100%. Among identical twin transplants from 2001 to 2017, excellent patient and kidney graft survival rates were noted. Approximately 50% of kidney transplant recipients of identical twins transplant did not receive maintenance immunosuppression, and no differences in graft survival were noted among patients with and without immunosuppression at 6 and 12 months (P = .8 and .7). Patients with glomerulonephritis as the cause of ESRF had lower graft survival (P = .06) suggesting that recurrent glomerulonephritis as a likely cause of graft loss among these recipients.

Donor acute kidney injury and its effect on 1-year post-transplant kidney allograft fibrosis.

Transplantation of kidneys from deceased donors with acute kidney injury (AKI) can expand the donor pool. We investigated the effect of donor AKI on renal function and chronic changes on protocol biopsies at 1-year post-transplant. Donor AKI was defined according to Acute Kidney Injury Network (AKIN) criteria. Between 2013 and 2017, 333 kidneys were transplanted and subsequently biopsied after 1 year. Fifty-three kidneys from AKI donors (AKIN stage I n = 42, stage II n = 8, stage III n = 3) were compared to 280 kidneys from non-AKI donors. At 1-year follow-up, patient and graft survival were comparable. Donor AKI was not predictive of IFTA (Banff interstitial fibrosis plus tubular atrophy scores) at 1-year post-transplant biopsy (2.10 ± 1.28 in AKI, 2.09 ± 1.22 in non-AKI, P = .95). Donor AKI was also not associated with progression of IFTA from 3 to 12 months (P = .69), or inferior glomerular filtration rate (eGFR, P = .94). In a multivariate analysis, the odds of IFTA >2 were comparable between AKI and non-AKI groups. In conclusion, the transplantation of kidneys from donors with predominantly stage I AKI results in comparable function and degree of fibrosis on protocol biopsies 1-year post-transplant. Selected grafts from donors with AKI are a valuable tool for expanding the donor pool for kidney transplantation.

A population neuroscience approach to the study of cerebral small vessel disease in midlife and late life: an invited review.

Aging in later life engenders numerous changes to the cerebral microvasculature. Such changes can remain clinically silent but are associated with greater risk for negative health outcomes over time. Knowledge is limited about the pathogenesis, prevention, and treatment of potentially detrimental changes in the cerebral microvasculature that occur with advancing age. In this review, we summarize literature on aging of the cerebral microvasculature, and we propose a conceptual framework to fill existing research gaps and advance future work on this heterogeneous phenomenon. We propose that the major gaps in this area are attributable to an incomplete characterization of cerebrovascular pathology, the populations being studied, and the temporality of exposure to risk factors. Specifically, currently available measures of age-related cerebral microvasculature changes are indirect, primarily related to parenchymal damage rather than direct quantification of small vessel damage, limiting the understanding of cerebral small vessel disease (cSVD) itself. Moreover, studies seldom account for variability in the health-related conditions or interactions with risk factors, which are likely determinants of cSVD pathogenesis. Finally, study designs are predominantly cross-sectional and/or have relied on single time point measures, leaving no clear evidence of time trajectories of risk factors or of change in cerebral microvasculature. We argue that more resources should be invested in 1) developing methodological approaches and basic science models to better understand the pathogenic and etiological nature of age-related brain microvascular diseases and 2) implementing state-of-the-science population study designs that account for the temporal evolution of cerebral microvascular changes in diverse populations across the lifespan.

Can Neuroimaging Markers of Vascular Pathology Explain Cognitive Performance in Adults With Sickle Cell Anemia? A review of the Literature.

Adults with homozygous sickle cell anemia have, on average, lower cognitive function than unaffected controls. The mechanisms underlying cognitive deterioration in this population are poorly understood, but cerebral small vessel disease (CSVD) is likely to be implicated. We conducted a systematic review using the Prisma Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines of articles that included both measures of cognitive function and magnetic resonance imaging (MRI) neuroimaging markers of small vessel disease. While all five studies we identified reported small vessel disease by MRI, only two of them found a significant relationship between structural changes and cognitive performance. Differences in methodologies and small sample sizes likely accounted for the discrepancies between the studies. We conclude that while MRI is a valuable tool to identify markers of CSVD in this population, larger studies are needed to definitely establish a link between MRI-detectable abnormalities and cognitive function in sickle cell anemia.

A glycine betaine importer limits Salmonella stress resistance and tissue colonization by reducing trehalose production.

Mechanisms by which Salmonella establish chronic infections are not well understood. Microbes respond to stress by importing or producing compatible solutes, small molecules that stabilize proteins and lipids. The Salmonella locus opuABCD (also called OpuC) encodes a predicted importer of the compatible solute glycine betaine. Under stress conditions, if glycine betaine cannot be imported, Salmonella enterica produce the disaccharide trehalose, a highly effective compatible solute. We demonstrate that strains lacking opuABCD accumulate more trehalose under stress conditions than wild-type strains. ΔopuABCD mutant strains are more resistant to high-salt, low-pH and -hydrogen peroxide, conditions that mimic aspects of innate immunity, in a trehalose-dependent manner. In addition, ΔopuABCD mutant strains require the trehalose production genes to out-compete wild-type strains in mice and macrophages. These data suggest that in the absence of opuABCD, trehalose accumulation increases bacterial resistance to stress in broth and mice. Thus, opuABCD reduces bacterial colonization via a mechanism that limits trehalose production. Mechanisms by which microbes limit disease may reveal novel pathways as therapeutic targets.

Impact of Subclinical and Clinical Kidney Allograft Rejection Within 1 Year Posttransplantation Among Compatible Transplant With Steroid Withdrawal Protocol.

Early acute kidney rejection remains an important clinical issue. METHODS: The current study included 552 recipients who had 1-2 surveillance or indication biopsy within the 1 y posttransplant. We evaluated the impact of type of allograft inflammation on allograft outcome. They were divided into 5 groups: no inflammation (NI: 95), subclinical inflammation (SCI: 244), subclinical T cell-mediated rejection (TCMR) (SC-TCMR: 110), clinical TCMR (C-TCMR: 83), and antibody-mediated rejection (AMR: 20). Estimated glomerular filtration rate (eGFR) over time using linear mixed model, cumulative chronic allograft scores/interstitial fibrosis and tubular atrophy (IFTA) ≥2 at 12 mo, and survival estimates were compared between groups. RESULTS: The common types of rejections were C-TCMR (15%), SC-TCMR (19.9%), and AMR (3.6%) of patients. Eighteen of 20 patients with AMR had mixed rejection with TCMR. Key findings were as follows: (i) posttransplant renal function: eGFR was lower for patients with C-TCMR and AMR (P < 0.0001) compared with NI, SCI, and SC-TCMR groups. There was an increase in delta-creatinine from 3 to 12 mo and cumulative allograft chronicity scores at 12 mo (P < 0.001) according to the type of allograft inflammation. (ii) Allograft histology: the odds of IFTA ≥2 was higher for SC-TCMR (3.7 [1.3-10.4]; P = 0.04) but was not significant for C-TCMR (3.1 [1.0-9.4]; P = 0.26), and AMR (2.5 [0.5-12.8]; P = 0.84) compared with NI group, and (iii) graft loss: C-TCMR accounted for the largest number of graft losses and impending graft losses on long-term follow-up. Graft loss among patient with AMR was numerically higher but was not statistically significant. CONCLUSIONS: The type of kidney allograft inflammation predicted posttransplant eGFR, cumulative chronic allograft score/IFTA ≥2 at 12 mo, and graft loss.

Moderately Macrosteatotic Livers Have Acceptable Long-Term Outcomes but Higher Risk of Immediate Mortality.

BACKGROUND AND AIMS: Liver transplantation is the most effective treatment for end-stage liver disease (ESLD). Whether moderately macrosteatotic livers (30%-60%) represent a risk for worsened graft function is controversial. The uncertainty, in large part, is owing to the heterogeneous steatosis grading. Our aim was to determine the short- and long-term outcomes of moderately macrosteatotic allografts that were graded according to a standardized institutional protocol. METHODS: We performed a retrospective analysis of transplants performed between 1994 and 2014. All patients with allografts biopsied pretransplantation were included. Relevant donor and recipient variable were recorded. Moderately macrosteatotic livers were compared with mildly macrosteatotic and nonsteatotic livers. Primary outcomes of interest were patient survival at 90 days, 1 year, and 5 years. Cox regression analyses were carried out to compare survival between the 2 groups. RESULTS: We compared 65 allografts with moderate macrosteatosis and 810 with no or mild macrosteatosis. Patients with moderately macrosteatotic allografts were 2.69 times as likely to die within the first 90 days after transplant (75.1% vs 91.6% survival) after adjusting for donor age, donor race, recipient age, recipient race, recipient body mass index, recipient diabetes, presence of hepatocellular carcinoma, days on waitlist, Model for End-Stage Liver Disease (MELD) score at transplantation, cold ischemia time. However, for recipients who survive 90 days, moderately macrosteatotic allografts had comparable long-term survival. CONCLUSION: Our study shows that moderate macrosteatosis is a strong predictor of early but not late mortality. Further studies are needed to distinguish the specific cohort of patients for whom moderately macrosteatotic allografts will lead to acceptable outcomes.

Cerebrovascular disease: Neuroimaging of cerebral small vessel disease.

The cerebral microvasculature is exceptionally vulnerable to changes due to aging. Both the radiological and clinical manifestations of cerebral small vessel disease (cSVD) in older age are highly heterogeneous, ranging from no symptomatology to devastating neurocognitive complications, including stroke, dementia, and depression. To date, the exact pathogenesis of cSVD is unknown; neither prevention nor treatments are currently available for this potentially very disabling condition. This chapter reviews recent advances in neuroimaging methodologies that have improved our understanding of the appearance of cSVD and the underlying mechanisms. We will discuss new venues for future research focusing on: (a) methodologies to measure early stages of cSVD, examining damage primarily in small vessels and secondarily in parenchyma; and (b) lifespan study designs to capture the onset and evolution of cSVD over time, as well as the temporality of exposure to risk factors.

The Impact of Early Clinical and Subclinical T Cell-mediated Rejection After Kidney Transplantation.

BACKGROUND: We investigated the effect of clinical and subclinical T cell-mediated rejection (C-TCMR and SC-TCMR) on allograft histology, function, and progression. METHODS: Adult kidney recipients with 2 protocol biopsies were divided into No-TCMR on biopsies (n = 104), SC-TCMR (n = 56), and C-TCMR (n = 32) in at least 1 biopsy. Chronicity (ci + ct + cg + cv) scores, renal function, and the burden of renal disease measured by area under the curve (serum creatinine, mg mo/dL) were compared. RESULTS: Baseline characteristics were similar except for mean donor age and Kidney Donor Profile index scores. Patients with C-TCMR had higher mean serum creatinine, lower mean estimated glomerular filtration rate, and higher area under the curve with 95% confidence interval (75.2 [67.7-82.7]) as opposed to patients with SC-TCMR and No-TCMR (58.3 [53.6-62.9], 65.1 [58.8-71.5]), P = 0.0004. Chronicity scores were higher at 3 months in C-TCMR (2.30 ± 1.58) compared with SC-TCMR (2.02 ± 1.42) and No-TCMR (1.31 ± 1.18), P = 0.0001 and also at 12 months. At last follow-up, 18.8% patients with C-TCMR had ≥50% decline in estimated glomerular filtration rate from 3 months compared with 7% and 1% among No-TCMR and SC-TCMR groups (P = 0.038). Multivariate analyses revealed higher odds of Δ-creatinine ≥ 0.5 mg/dL from 3 months to last follow-up for C-TCMR (3.39 [95% confidence interval, 1.25-9.20]) versus No-TCMR (P = 0.016). CONCLUSIONS: Kidney transplant recipients with C-/SC-TCMR have heightened early allograft chronicity and worse renal function compared with those with No-TCMR. Progressive renal dysfunction was noted among patients with C-TCMR as opposed to SC-TCMR and No-TCMR.

Physical Activity and Cerebral Small Vein Integrity in Older Adults.

Identifying promoters of cerebral small vein integrity is important to counter vascular contributions to cognitive impairment and dementia. PURPOSE: In this preliminary investigation, the effects of a randomized 24-month physical activity (PA) intervention on changes in cerebral small vein integrity were compared to those of a health education (HE) control. METHODS: Cerebral small vein integrity was measured in 24 older adults (n = 8, PA; n = 16, HE) using ultra-high field MRI before and at the end of the 24-month intervention. Deep medullary veins were defined as straight or tortuous; percent change in straight length, tortuous length, and tortuosity ratio were computed. Microbleed count and white matter hyperintensities were also rated. RESULTS: Accelerometry-based values of PA increased by 17.2% in the PA group but declined by 28.0% in the HE group. The PA group, but not the HE group, had a significant increase in straight vein length from baseline to 24-month follow-up (P = 0.02 and P = 0.21, respectively); the between-group difference in percent change in straight length was significant (increase: median, 93.6%; interquartile range, 112.9 for PA; median, 28.4%; interquartile range, 90.6 for HE; P = 0.07). Between group differences in other markers were nonsignificant. CONCLUSIONS: Increasing PA in late-life may promote cerebral small vein integrity. This should be confirmed in larger studies.

Disease severity and slower psychomotor speed in adults with sickle cell disease.

Psychomotor slowing is common in children with sickle cell disease (SCD), but little is known about its severity in adults. We conducted a cross-sectional study to quantify psychomotor speed, measured with the digit symbol substitution test (DSST), in relationship with disease severity in adults with SCD attending an outpatient clinic (n = 88, age 36.3 years). Genotype was used to group patients in "severe" (homozygous for hemoglobin S or compound heterozygous with ß0 thalassemia) or "moderate" groups (compound heterozygous for HbS, with either HbC or ß+ thalassemia). Analyses were repeated after exclusion of patients with a history of stroke (n = 11). Mild impairment in processing speed was detectable in both the "severe" and the "moderate" group (30% and 9%, respectively; age-adjusted P = .14). Compared with the "moderate" group, those in the "severe" group had significantly lower standardized DSST scores (P = .004), independent of adjustment for factors that differed between the groups: hemoglobin, ferritin, hydroxyurea use, blood pressure parameters, and stroke history. Results were similar after excluding patients with stroke. Psychomotor slowing in SCD differs in relationship to genotype; this difference appears unrelated to history of stroke or severity of anemia and other risk factors examined cross-sectionally. Although less prevalent, mild cognitive impairment was also detectable in patients with a less severe genotype. Longitudinal studies of SCD should include all diseases genotypes and examine factors that would reduce the risk of slow processing speed and perhaps more general cognitive impairment in each subgroup.