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OBJECTIVES/GOALS: Assess molecular and cellular mechanisms of allograft loss in kidney biopsies using digital spatial profiling and clinical outcomes data. METHODS/STUDY POPULATION: Patients with chronic allograft dysfunction (CGD), enrolled in the Deterioration of Kidney Allograft Function (DeKAF) study, with or without eventual allograft loss, were included. CGD was defined as a >25% increase in creatinine over 3 months relative to a baseline. Kidney biopsy tissue was assessed by Nanostring GeoMX digital spatial profiling (DSP) after staining with anti-pan-cytokeratin, anti-CD45, anti-CD68, Syto-13, to identify specific cell populations, and Nanostring’s Whole Transcriptome Atlas (WTA), to quantify the distribution of transcripts across the biopsy. Up to 14 regions of interest (ROIs) were selected, with or without glomerulus. CIBERSORT was used to perform cell deconvolution. Clinical and outcomes data were from the DeKAF study and United States Renal Data System. RESULTS/ANTICIPATED RESULTS: Macrophage (M1) cell population abundance was significantly different in ROIs with glomerulus between graft loss and no graft loss. Principle component analysis of differentially expressed genes resulted in transcriptomes in ROIs that cluster together by clinical outcome of graft loss or no graft loss. There were 203 DEGs in ROIs with glomerulus that were different by graft loss or no graft loss. By pathway analysis, these 203 DEGS were enriched in the T-cell activation, integrin signaling and inflammation pathways. DISCUSSION/SIGNIFICANCE: DSP of kidney allograft biopsies allows for the identification and quantification of specific cell types, such as macrophages and molecular transcripts as potential drug targets. This data can be used to understand mechanisms of kidney allograft loss and may lead to improved immune suppression in kidney transplant recipients.

The document titled "487 Digital Spatial Profiling of Allograft Loss in Kidney Biopsies with Chronic Allograft Dysfunction" discusses the use of digital spatial profiling to assess molecular and cellular mechanisms of allograft loss in kidney biopsies. The study analyzes kidney biopsy tissue from patients with chronic allograft dysfunction and uses Nanostring GeoMX digital spatial profiling to identify specific cell populations and quantify the distribution of transcripts across the biopsy. The results show differences in cell populations and gene expression between biopsies with graft loss and those without. This data can help understand the mechanisms of kidney allograft loss and potentially improve immune suppression in kidney transplant recipients. [Extracted from the article]

Aims: Tacrolimus, metabolized by CYP3A4 and CYP3A5 enzymes, is susceptible to drug-drug interactions (DDI). Steroids induce CYP3A genes to increase tacrolimus clearance, but the effect is variable. We hypothesized that the extent of the steroid-tacrolimus DDI differs by CYP3A4/5 genotypes., Methods: Kidney transplant recipients (n = 2462) were classified by the number of loss of function alleles (LOF) (CYP3A5*3, *6 and *7 and CYP3A4*22) and steroid use at each tacrolimus trough in the first 6 months post-transplant. A population pharmacokinetic analysis was performed by nonlinear mixed-effect modelling (NONMEM) and stepwise covariate modelling to define significant covariates affecting tacrolimus clearance. A stochastic simulation was performed and translated into a Shiny application with the mrgsolve and Shiny packages in R., Results: Steroids were associated with modestly higher (3%-11.8%) tacrolimus clearance. Patients with 0-LOF alleles receiving steroids showed the greatest increase (11.8%) in clearance compared to no steroids, whereas those with 2-LOFs had a negligible increase (2.6%) in the presence of steroids. Steroid use increased tacrolimus clearance by 5% and 10.3% in patients with 1-LOF and 3/4-LOFs, respectively., Conclusions: Steroids increase the clearance of tacrolimus but vary slightly by CYP3A genotype. This is important in individuals of African ancestry who are more likely to carry no LOF alleles, may more commonly receive steroid treatment, and will need higher tacrolimus doses., (© 2024 The Author(s). British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

The human microbiome is associated with human health and disease. Exogenous compounds, including pharmaceutical products, are also known to be affected by the microbiome, and this discovery has led to the field of pharmacomicobiomics. The microbiome can also alter drug pharmacokinetics and pharmacodynamics, possibly resulting in side effects, toxicities, and unanticipated disease response. Microbiome-mediated effects are referred to as drug-microbiome interactions (DMI). Rapid advances in the field of pharmacomicrobiomics have been driven by the availability of efficient bacterial genome sequencing methods and new computational and bioinformatics tools. The success of fecal microbiota transplantation for recurrent Clostridioides difficile has fueled enthusiasm and research in the field. This review focuses on the pharmacomicrobiome in transplantation. Alterations in the microbiome in transplant recipients are well documented, largely because of prophylactic antibiotic use, and the potential for DMI is high. There is evidence that the gut microbiome may alter the pharmacokinetic disposition of tacrolimus and result in microbiome-specific tacrolimus metabolites. The gut microbiome also impacts the enterohepatic recirculation of mycophenolate, resulting in substantial changes in pharmacokinetic disposition and systemic exposure. The mechanisms of these DMI and the specific bacteria or communities of bacteria are under investigation. There are little or no human DMI data for cyclosporine A, corticosteroids, and sirolimus. The available evidence in transplantation is limited and driven by small studies of heterogeneous designs. Larger clinical studies are needed, but the potential for future clinical application of the pharmacomicrobiome in avoiding poor outcomes is high., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

African American (AA) kidney transplant recipients (KTRs) have poor outcomes, which may in-part be due to tacrolimus (TAC) sub-optimal immunosuppression. We previously determined the common genetic regulators of TAC pharmacokinetics in AAs which were CYP3A5 *3, *6, and *7. To identify low-frequency variants that impact TAC pharmacokinetics, we used extreme phenotype sampling and compared individuals with extreme high (n = 58) and low (n = 60) TAC troughs (N = 515 AA KTRs). Targeted next generation sequencing was conducted in these two groups. Median TAC troughs in the high group were 7.7 ng/ml compared with 6.3 ng/ml in the low group, despite lower daily doses of 5 versus 12 mg, respectively. Of 34,542 identified variants across 99 genes, 1406 variants were suggestively associated with TAC troughs in univariate models (p-value < 0.05), however none were significant after multiple testing correction. We suggest future studies investigate additional sources of TAC pharmacokinetic variability such as drug-drug-gene interactions and pharmacomicrobiome., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

The transplantation of organ(s) across species may alleviate the shortage of available donor kidneys for an ever-growing number of patients on transplant waiting lists. However, this potential remains limited by uncharacterized physiologic and immune effects of xenotransplants in recipients, which Pan et al. 1 investigated in the current study., Competing Interests: Declaration of interests A.K.I. has served on an advisory board for Avera Pharmaceuticals and Novartis, receives consulting fees from the Medical Review Institute of America, and has family members that are employees of Novartis pharmaceutical company, all of which are unrelated to this work., (Copyright © 2024. Published by Elsevier Inc.)

Background: Therapeutic drug monitoring for mycophenolic acid (MPA) is challenging due to difficulties in measuring the area under the curve (AUC). Limited sampling strategies (LSSs) have been developed for MPA therapeutic drug monitoring but come with risk of unacceptable performance. The authors hypothesized that the poor predictive performance of LSSs were due to the variability in MPA enterohepatic recirculation (EHR). This study is the first to evaluate LSSs models performance in the context of EHR., Methods: Adult kidney transplant recipients (n = 84) receiving oral mycophenolate mofetil underwent intensive MPA pharmacokinetic sampling. MPA AUC0-12hr and EHR were determined. Published MPA LSSs in kidney transplant recipients receiving tacrolimus were evaluated for their predictive performance in estimating AUC0-12hr in our full cohort and separately in individuals with high and low EHR., Results: None of the evaluated LSS models (n = 12) showed good precision or accuracy in predicting MPA AUC0-12hr in the full cohort. In the high EHR group, models with late timepoints had better accuracy but low precision, except for 1 model with late timepoints at 6 and 10 hours postdose, which had marginally acceptable precision. For all models, the good guess of predicted AUC0-12hr (±15% of observed AUC0-12hr) was highly variable (range, full cohort = 19%-61.9%; high EHR = 4.5%-65.9%; low EHR = 27.5%-62.5%)., Conclusions: The predictive performance of the LSS models varied according to EHR status. Timepoints ≥5 hours postdose in LSS models are essential to capture EHR. Models and strategies that incorporate EHR during development are required to accurately ascertain MPA exposure., Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Though the microbiome's impact on immune system homeostasis is well documented, the effect of circulating T cells on the gut microbiome remains unexamined. We analyzed data from 50 healthy volunteers in a pilot trial of aspirin, using immunophenotyping and 16S rRNA sequencing to evaluate the effect of baseline T cells on microbiome changes over 6 weeks. We employed an unsupervised sparse canonical correlation analysis (sCCA) and used multivariable linear regression models to evaluate the association between selected T cell subsets and selected bacterial genera after adjusting for covariates. In the cross-sectional analysis, percentages of naïve CD4+ T cells were positively associated with a relative abundance of Intestinimonas , and the percentage of activated CD8+ T cells was inversely associated with Cellulosibacter . In the longitudinal analysis, the baseline percentages of naïve CD4+ T cells and activated CD4+ T cells were inversely associated with a 6-week change in the relative abundance of Clostridium&#95;XlVb and Anaerovorax , respectively. The baseline percentage of terminal effector CD4+ T cells was positively associated with the change in Flavonifractor . Notably, the microbiome taxa associated with T cell subsets exclusively belonged to the Bacillota phylum . These findings can guide future experimental studies focusing on the role of T cells in impacting gut microbiome homeostasis.

Ginger has been associated with a decreased incidence of colorectal cancer (CRC) through reduction in inflammatory pathways and inhibition of tumor growth. Recent pre-clinical models have implicated changes in the gut microbiome as a possible mediator of the ginger effect on CRC. We hypothesized that, in adults previously diagnosed with a colorectal adenoma, ginger supplementation would alter the fecal microbiome in the direction consistent with its CRC-inhibitory effect. Sixty-eight adults were randomized to take either ginger or placebo daily for 6 weeks, with a 6-week washout and longitudinal stool collection throughout. We performed 16S rRNA sequencing and evaluated changes in overall microbial diversity and the relative abundances of pre-specified CRC-associated taxa using mixed-effects logistic regression. Ginger supplementation showed no significant effect on microbial community structure through alpha or beta diversity. Of 10 pre-specified CRC-associated taxa, there were significant decreases in the relative abundances of the genera Akkermansia (p < 0.001), Bacteroides (p = 0.018), and Ruminococcus (p = 0.013) after 6-week treatment with ginger compared to placebo. Ginger supplementation led to decreased abundances of Akkermansia and Bacteroides, which suggests that ginger may have an inhibitory effect on CRC-associated taxa. Overall, ginger supplementation appears to have a limited effect on gut microbiome in patients with colorectal adenomas., (© 2024. The Author(s).)

Kidney transplant recipients carrying the CYP3A5*1 allele have lower tacrolimus troughs, and higher dose requirements compared to those with the CYP3A5*3/*3 genotype. However, data on the effect of CYP3A5 alleles on post-transplant tacrolimus management are lacking. The effect of CYP3A5 metabolism phenotypes on the number of tacrolimus dose adjustments and troughs in the first 6 months post-transplant was evaluated in 78 recipients (64% Caucasians). Time to first therapeutic concentration, percentage of time in therapeutic range (TTR), and estimated glomerular filtration rate (eGFR) were also evaluated. Fifty-five kidney transplant recipients were CYP3A5 poor metabolizers (PM), 17 were intermediate metabolizers (IM), and 6 were extensive metabolizers (EM). Compared to PMs, EMs/IMs had significantly more dose adjustments (6.1 vs. 8.1, p = .015). Overall, 33.82% of trough measurements resulted in a dose change. There was no difference in the number of tacrolimus trough measurements between PMs and EM/IMs. The total daily tacrolimus dose requirements were higher in EMs and IMs compared to PMs (<.001). TTR was ∼50% in the PMs and EMs/IMs groups. CYP3A5 EM/IM metabolizers have more tacrolimus dose changes and higher dose requirements which increases clinical management complexity. Larger studies are needed to assess the cost and benefits of including genotyping data to improve clinical management., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Individuals with cystic fibrosis (CF), caused by biallelic germline mutations in the cystic fibrosis transmembrane conductance regulator ( CFTR) , have higher risk and earlier onset of colorectal cancer (CRC). A subset of CRC patients in the non-CF population expresses low levels of tumoral CFTR mRNA which may also cause decreased CFTR activity. To determine the consequences of reduced CFTR expression in this population, we investigated association of tumoral CFTR expression with overall and disease-specific mortality in CRC patients. CFTR mRNA expression, clinical factors and survival data from 1177 CRC patients reported in the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus studies GSE39582 and GSE17538 were included. Log-transformed and z-normalized [mean = 0, standard deviation (SD) = 1] CFTR expression values were modeled as quartiles or dichotomized at the median. Univariate and multivariable Cox proportional hazards regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for overall and disease-specific mortality in individual studies and meta-analyses. Analyses of each of the three individual datasets showed a robust association of decreased CFTR expression with increased mortality. In meta-analyses adjusted for stage at diagnosis, age and sex, CFTR expression was inversely associated with risk of overall death [pooled HR (95% CI): 0.70 (0.57-0.86)] and disease-specific death [pooled HR (95% CI): 0.68 (0.47-0.99)]. Associations did not differ by stage at diagnosis, age, or sex. Meta-analysis of overall death stratified by microsatellite instable (MSI) versus microsatellite stable (MSS) status indicated potential interaction between MSI/MSS status and CFTR expression, ( p -interaction: 0.06). The findings from these three datasets support the hypothesis that low CFTR expression is associated with increased CRC mortality.

Background: Adherence to the World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) cancer prevention recommendations is associated with colorectal cancer (CRC) risk in whites, but only 1 previous study has reported on this link in African Americans. This study assessed the association between the 2018 WCRF/AICR guidelines and CRC incidence in African Americans (26.5%) and whites (73.5%) in the Atherosclerosis Risk in Communities prospective cohort (n = 13,822)., Methods: A total of 368 incident CRC cases (268 among whites and 100 among African Americans) were identified between the baseline (1987) and 2012. A baseline adherence score was created for 7 WCRF/AICR guidelines (each contributing 0, 0.5, or 1 point to the score, with higher scores corresponding to greater adherence). Adherence scores were also categorized as tertiles (0.0-3.0, 3.5-4.0, and 4.5-7.0). Cox proportional hazards regression was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for the total cohort and with stratification by race., Results: After adjustments for age, sex, race, center, smoking, education, intake of aspirin, calcium, total calories, diabetes status, and, in women, hormone replacement therapy, greater adherence was associated with decreased CRC risk. The HRs per 1-unit increment in score were 0.88 (95% CI, 0.80-0.97) for the whole cohort, 0.89 (95% CI, 0.73-1.09) for African Americans, and 0.88 (95% CI, 0.77-0.99) for whites. Similar associations between higher adherence scores and decreased cancer risk were observed for men and women and for colon cancer but not for rectal cancer., Conclusions: Greater adherence to the cancer prevention recommendations appears to be associated with decreased CRC risk for both African Americans and whites., (© 2019 American Cancer Society.)

Purpose: Previous studies have reported that taller people have an increased risk of colorectal cancer (CRC). We examined the association of two height components-leg length and sitting height-with CRC risk in 14,532 individuals aged 45-64 years in the Atherosclerosis Risk in Communities study., Methods: Anthropometrics were measured at baseline (1987-1989). Incident CRC cases (n = 382) were ascertained from 1987 to 2012. Cox proportional hazards regression was used to estimate multivariable-adjusted hazard ratios for CRC and colon cancer across quintiles of sex-specific leg length and sitting height., Results: The highest (versus the lowest) quintile of leg length was associated with a 36% greater CRC risk (p-trend = 0.04), and 51% greater colon cancer risk (p-trend = 0.01). For the top four quintiles combined, risk was increased by 34% for CRC and by 45% for colon cancer versus the lowest quintile. Total height and sitting height were not significantly associated with CRC or colon cancer risk. A small number of cases (n = 57) limited our ability to conduct subgroup analyses for rectal cancer., Conclusions: A positive association of leg length with CRC and colon cancer risk suggests that biological mechanisms leading to greater leg length during puberty may explain the association between taller height and CRC.

Background: Laboratory and epidemiologic research suggests a protective role of magnesium in colorectal cancer development. We estimated the associations of serum and dietary magnesium with colorectal cancer incidence in the Atherosclerosis Risk in Communities (ARIC) study., Methods: Serum magnesium concentration was measured in blood collected twice (1987-1989 and 1990-1992) and averaged. Dietary magnesium was assessed by food-frequency questionnaire administered twice (1987-1989 and 1993-1995) and averaged. For both dietary and serum magnesium, the averaged measures were categorized into quintiles for analysis. Analyses included 315 colorectal cancer cases among 13,009 participants for serum magnesium (followed for a median of 20.4 years), and 256 cases among 10,971 participants for dietary magnesium (followed for a median of 17.5 years). Cox proportional hazards regression was used to calculate multivariable-adjusted HRs and 95% confidence intervals (CI)., Results: Multivariable-adjusted HRs (95% CI) of colorectal cancer for the highest four quintiles compared with the first quintile of serum magnesium were as follows: Q2: 0.70 (0.49-0.99); Q3: 0.68 (0.47-1.00); Q4: 0.87 (0.62-1.21); and Q5: 0.79 (0.57-1.11; P trend = 0.04). An inverse association was present in females (HR for Q5 vs. Q1: 0.59, 95% CI: 0.36-0.98, P trend = 0.01), but not males (HR for Q5 vs. Q1: 1.10, 95% CI: 0.67-1.79, P trend = 0.92; P interaction = 0.34). Dietary magnesium was not statistically significantly associated with colorectal cancer risk., Conclusions: Our study found a higher risk of colorectal cancer with lower serum magnesium among females, but not males., Impact: If our findings are confirmed, maintaining adequate serum magnesium levels may be important for colorectal cancer prevention., (©2019 American Association for Cancer Research.)

Background: Pancreatic tumor cells may avoid immune surveillance by releasing the transmembrane major histocompatibility complex class I chain-related A (MICA) protein in soluble form (s-MICA). We hypothesized that the presence of the A5.1 polymorphism in the MICA gene, which encodes a truncated MICA protein, is associated with higher s-MICA levels and increased pancreatic cancer risk., Methods: MICA alleles and s-MICA levels were measured in 121 pancreatic cancer cases and 419 controls. General linear regression with a log transformation assessed geometric means of s-MICA levels across MICA alleles. Unconditional logistic regression was used to calculate the odds ratio (OR) and 95% confidence intervals (CI) for pancreatic cancer associated with MICA alleles., Results: After multivariate adjustment, participants with at least one copy of the A5.1 allele versus no A5.1 allele had 1.35 (95% CI: 1.05-1.74) times greater s-MICA levels (1.65 times higher for cases and 1.28, for controls) and increased risk of pancreatic cancer (OR = 1.91, 95% CI: 1.05-3.48)., Conclusions: Our study suggests higher risk of pancreatic cancer among those with the MICA A5.1 polymorphism, which may be explained by an increase in s-MICA secretion and impaired immune response., Impact: These findings provide further evidence at the genetic and molecular level of the important role of MICA in pancreatic cancer development, and may have important implications with regards to pancreatic cancer screening., Competing Interests: The authors have declared that no competing interests exist.

Pancreatic cancer is diagnosed at a late stage and has one of the highest cancer mortality rates in the United States, creating an urgent need for novel early detection tools. A candidate biomarker for use in early detection is the soluble MHC class I-related chain A (s-MICA) ligand, which pancreatic tumors shed to escape immune detection. The objective of this study was to define the association between s-MICA levels and pancreatic cancer, in a population-based case-control study. S-MICA was measured in 143 pancreatic cancer cases and 459 controls. Unconditional logistic regression was used to calculate odds ratio (OR) for pancreatic cancer and 95% confidence intervals (CI). There was a positive association between increasing s-MICA levels and pancreatic cancer: compared to the lowest tertile, the ORs for pancreatic cancer were 1.25 (95%CI: 0.75-2.07) and 2.10 (95%CI: 1.29-3.42) in the second and highest tertiles, respectively (P-trend = 0.02). Our study supports previous work demonstrating a positive association between plasma s-MICA levels and pancreatic cancer., (© 2017 Wiley Periodicals, Inc.)