Net Endogenous Acid Excretion and Kidney Allograft Outcomes

Author(s):  
Stanley Yeung ◽  
Antonio Gomes-Neto ◽  
Maryse Osté ◽  
Else van den Berg ◽  
Jenny Kootstra-Ros ◽  
...  

Background and objectives: High dietary acid load may accelerate kidney function decline. We prospectively investigated whether dietary acid load is associated with graft outcomes in kidney transplant recipients and whether venous bicarbonate (HCO3−) mediates this association. Design, setting, participants and measurements: We used data from 642 kidney transplant recipients with a functioning graft ≥1 year after transplantation. Net endogenous acid production (NEAP) was estimated using food frequency questionnaires (FFQ) and, alternatively, 24-hour urinary urea and potassium excretion to estimate NEAPUrine. We defined composite kidney endpoint as doubling of plasma creatinine or graft failure. Multivariable Cox regression analyses, adjusted for potential confounders, were used to study the associations of dietary acid load with kidney endpoint. We evaluated potential mediation effects of venous HCO3− , urinary HCO3− excretion, urinary ammonium (NH4+) excretion, titratable acid excretion, and net acid excretion on the association between NEAP and kidney endpoint. Results: Median NEAPFFQ and NEAPUrine were 40 (Interquartile range [IQR] 35-45) and 54 (IQR 44-66) mEq/day, respectively. During a median follow-up time of 5.3 (IQR 4.1-6.0) years, 121 (19%) participants reached kidney endpoint. After multivariable adjustment, NEAPFFQ and NEAPUrine (per SD higher) were independently associated with higher risk for kidney endpoint (hazard ratio [HR] 1.33; 95% confidence interval [CI] 1.12-1.57, P=0.001 and HR 95%CI, 1.44 [1.24-1.69], P<0.001 resp.). Baseline venous HCO3− mediated 20% of the association between NEAPFFQ and kidney endpoint. Baseline venous HCO3−, urinary NH4+ excretion and net acid excretion mediated 25%, -14% and -18% resp. of the association between NEAPUrine and kidney endpoint. Conclusion: Higher dietary acid load was associated with a higher risk of doubling of plasma creatinine or graft failure, and this association was partly mediated by venous HCO3−, urinary NH4+ and net acid excretion.

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Stanley Ming Hol Yeung ◽  
António W Gomes-Neto ◽  
Maryse C.J. Osté ◽  
Else Van den Berg ◽  
Jenny E Kootstra-Ros ◽  
...  

Abstract Background and Aims Dietary acid load is associated with low grade metabolic acidosis and might accelerate kidney function decline in patients with chronic kidney disease (CKD). We investigated whether dietary acid load, estimated as net endogenous acid production (NEAP), is associated with kidney function decline in kidney transplant recipients (KTR) and to what extent this association is mediated by variation in venous bicarbonate (HCO3-). Method We used data from 642 KTR with a functioning graft ≥1 year after transplantation who were enrolled in the Transplantlines Food & Nutrition Cohort Study between 2008-2011. We applied the Frassetto equation (NEAP = (54.5 X protein (g/d) / potassium (mEq/d) - 10.2)) to calculate NEAPFFQ using intake reported in food frequency questionnaires and NEAPUrine from assessments of 24 hours urinary urea and potassium excretion. Patients were divided into tertiles of NEAP and differences across tertiles were analyzed by ANOVA, Kruskall-Wallis and Chi-Square tests, as appropriate. Cox regression models were used to study the associations between NEAPFFQ and NEAPUrine (both continuous variables and categories) with the composite endpoint kidney function decline, defined as doubling of serum creatinine or graft failure. Mediation analyses were performed to evaluate whether these associations were explained by venous bicarbonate. Results Mean age was 53±13 years, 56.1% were men, and mean eGFR was 52±20 ml/min/1.73m2. Patients within the highest tertile of NEAPFFQ were younger (P=0.04), more recently transplanted (P=0.002), consumed less fruit and vegetables (P&lt;0.001), more fish (P=0.001), less alcohol (P=0.01), more meat (P&lt;0.001) and had lower serum HCO3- concentration (P=0.02). During a median follow-up time of 5.3 (4.1-6.0) years, 121 (18.8%) patients developed kidney function decline. In multivariable Cox regression analysis, higher NEAPFFQ (per SD increase) was associated with increased risk of kidney function decline, independent of potential confounders, including age, sex, BMI, time after transplantation, primary kidney disease, eGFR and proteinuria (adjusted HR 1.30; 95%CI 1.10-1.53, P=0.002). Compared to patients in the lowest NEAPFFQ tertile, those in the highest tertile had a &gt;1.5 higher risk of kidney function decline (adjusted HR 1.67; 95%CI 1.07-2.62, P=0.03). We observed similar results using NEAPUrine as the study exposure (adjusted HR 1.46 per SD increase; 95%CI 1.24-1.73, P&lt;0.001; adjusted HR 1.99; 95%CI 1.24-3.18, P=0.004 for patients in the highest versus lowest tertile of NEAPUrine). These associations between NEAPFFQ (Figure A) and NEAPUrine (Figure B) with kidney function decline were visualized by fitting multivariable Cox regression models based on restricted cubic splines. Mediation analyses estimated that venous HCO3- at baseline mediated 19.3% (P=0.008) of the association between NEAPFFQ and kidney function decline and 26.5% (P=0.002) of the association between NEAPUrine with kidney function decline. Conclusion Higher NEAP is associated with a higher risk for kidney function decline in KTR, and this association was in part mediated by venous HCO3-. We speculate that reducing dietary acid load might mitigate the risk of kidney function decline in KTR.


Antioxidants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1102
Author(s):  
Angelica Rodriguez-Niño ◽  
Diego O. Pastene ◽  
Adrian Post ◽  
M. Yusof Said ◽  
Antonio W. Gomes-Neto ◽  
...  

Carnosine affords protection against oxidative and carbonyl stress, yet high concentrations of the carnosinase-1 enzyme may limit this. We recently reported that high urinary carnosinase-1 is associated with kidney function decline and albuminuria in patients with chronic kidney disease. We prospectively investigated whether urinary carnosinase-1 is associated with a high risk for development of late graft failure in kidney transplant recipients (KTRs). Carnosine and carnosinase-1 were measured in 24 h urine in a longitudinal cohort of 703 stable KTRs and 257 healthy controls. Cox regression was used to analyze the prospective data. Urinary carnosine excretions were significantly decreased in KTRs (26.5 [IQR 21.4–33.3] µmol/24 h versus 34.8 [IQR 25.6–46.8] µmol/24 h; p < 0.001). In KTRs, high urinary carnosinase-1 concentrations were associated with increased risk of undetectable urinary carnosine (OR 1.24, 95%CI [1.06–1.45]; p = 0.007). During median follow-up for 5.3 [4.5–6.0] years, 84 (12%) KTRs developed graft failure. In Cox regression analyses, high urinary carnosinase-1 excretions were associated with increased risk of graft failure (HR 1.73, 95%CI [1.44–2.08]; p < 0.001) independent of potential confounders. Since urinary carnosine is depleted and urinary carnosinase-1 imparts a higher risk for graft failure in KTRs, future studies determining the potential of carnosine supplementation in these patients are warranted.


2021 ◽  
Vol 2 (3) ◽  
pp. 253-263
Author(s):  
Het Patel ◽  
Nikhil Agrawal ◽  
Voravech Nissaisorakarn ◽  
Ridhi Gupta ◽  
Francesca Cardarelli

Malignancy is the third major cause of death among transplant recipients. Patient and kidney transplant outcomes after the diagnosis of malignancy are not well described. We reviewed incidences and outcomes of colorectal, lung, PTLD, and renal malignancy after transplant among patients who received a transplant from January 2000 to December 2018 using the UNOS/OPTN database. Incidence of each malignancy was measured at 5 years and 10 years of transplant. The Kaplan–Meier curve was used for time-to-event analysis (graft and patient outcomes). Additionally, we sought to identify the causes of graft failure among these recipients. We found that 12,764 (5.5%) patients suffered malignancy, excluding squamous and basal cell skin carcinoma after transplant. During the first 5 years of transplant, incidence of colorectal, lung, PTLD, and renal malignancies was 2.99, 9.21, 15.61, and 8.55 per 10,000 person-years, respectively. Rates of graft failure were 10.3%, 7.6%, 19.9%, and 18.8%, respectively, among these patients at 5 years. Mortality rate was highest among patients who suffered lung malignancy (84%), followed by colorectal (61.5%), PTLD (49.1%), and renal (35.5%) at 5 years after diagnosis of malignancy. In conclusion, kidney transplant recipients diagnosed with lung malignancy have the lowest graft survival, compared to PTLD, colorectal, and renal malignancy. PTLD has the highest incidence rate in the first 5 years of transplant.


Diseases ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 2
Author(s):  
Maria L. Gonzalez Suarez ◽  
Charat Thongprayoon ◽  
Panupong Hansrivijit ◽  
Juan Medaura ◽  
Pradeep Vaitla ◽  
...  

Background: Fabry disease (FD) is a rare X-linked lysosomal storage disorder with progressive systemic deposition of globotriaosylceramide, leading to life-threatening cardiac, central nervous system, and kidney disease. Current therapy involves symptomatic medical management, enzyme replacement therapy (ERT), dialysis, kidney transplantation, and, more recently, gene therapy. The aim of this systematic review was to assess outcomes of kidney transplantation among patients with FD. Methods: A comprehensive literature review was conducted utilizing MEDLINE, EMBASE, and Cochrane Database, from inception through to 28 February 2020, to identify studies that evaluate outcomes of kidney transplantation including patient and allograft survival among kidney transplant patients with FD. Effect estimates from each study were extracted and combined using the random-effects generic inverse variance method of DerSimonian and Laird. Results: In total, 11 studies, including 424 kidney transplant recipients with FD, were enrolled. The post-transplant median follow-up time ranged from 3 to 11.5 years. Overall, the pooled estimated rates of all-cause graft failure, graft failure before death, and allograft rejection were 32.5% (95%CI: 23.9%–42.5%), 14.5% (95%CI: 8.4%–23.7%), and 20.2% (95%CI: 15.4%–25.9%), respectively. In the sensitivity analysis, limited only to the recent studies (year 2001 or newer when ERT became available), the pooled estimated rates of all-cause graft failure, graft failure before death, and allograft rejection were 28.1% (95%CI: 20.5%–37.3%), 11.7% (95%CI: 8.4%–16.0%), and 20.2% (95%CI: 15.5%–26.0%), respectively. The pooled estimated rate of biopsy proven FD recurrence was 11.1% (95%CI: 3.6%–29.4%), respectively. There are no significant differences in the risks of all-cause graft failure (p = 0.10) or mortality (0.48) among recipients with vs. without FD. Conclusions: Despite possible FD recurrence after transplantation of 11.1%, allograft and patient survival are comparable among kidney transplant recipients with vs. without FD.


2021 ◽  
Vol 31 (4) ◽  
pp. 288-297
Author(s):  
Tanya Kuper ◽  
Olusegun Famure ◽  
Jamie Greenfield ◽  
Yanhong Li ◽  
Syed Ibrahim ◽  
...  

Introduction: Proteinuria is recognized as an independent risk factor for cardiovascular disease in kidney transplant recipients, but previous studies have not considered the impact of changes in urine protein over time. Research Question and Design: We used time-dependent, multivariable Cox proportional hazards models in this observational cohort study of adult kidney transplant recipients to evaluate whether proteinuria measured by dipstick on random spot urine samples starting from 1-month post-transplant was associated with the risk of major adverse cardiac events and graft loss. Results: A total of 144 major adverse cardiac events, defined as acute myocardial infarction, cerebrovascular accident, revascularization, or all-cause mortality, were observed in 1106 patients over 5728.7 person-years. Any level of proteinuria greater or equal to trace resulted in a two-fold increase in the risk of major adverse cardiac events (hazard ratio 2.00 [95% confidence interval 1.41, 2.84]). This relationship was not found to be dose-dependent (hazard ratios of 2.98, 1.76, 1.63, and 1.54 for trace, 1+, 2+, and 3+ urine protein, respectively). There was an increased risk of graft failure with greater urine protein concentration (hazard ratios 2.22, 2.85, 6.41, and 19.71 for trace, 1+, 2+, and 3+, respectively). Conclusion: Urine protein is associated with major adverse cardiac events and graft loss in kidney transplant recipients. The role of interventions to reduce proteinuria on decreasing the risk of adverse cardiovascular and graft outcomes in kidney transplant recipients requires further study.


2014 ◽  
Vol 97 (9) ◽  
pp. 925-933 ◽  
Author(s):  
Jeffrey J. Gaynor ◽  
Gaetano Ciancio ◽  
Giselle Guerra ◽  
Junichiro Sageshima ◽  
Lois Hanson ◽  
...  

Author(s):  
Hilda E. Fernandez ◽  
Bethany J. Foster

Pediatric kidney transplant recipients are distinguished from adult recipients by the need for many decades of graft function, the potential effect of CKD on neurodevelopment, and the changing immune environment of a developing human. The entire life of an individual who receives a transplant as a child is colored by their status as a transplant recipient. Not only must these young recipients negotiate all of the usual challenges of emerging adulthood (transition from school to work, romantic relationships, achieving independence from parents), but they must learn to manage a life-threatening medical condition independently. Regardless of the age at transplantation, graft failure rates are higher during adolescence and young adulthood than at any other age. All pediatric transplant recipients must pass through this high-risk period. Factors contributing to the high graft failure rates in this period include poor adherence to treatment, potentially exacerbated by the transfer of care from pediatric- to adult-oriented care providers, and perhaps an increased potency of the immune response. We describe the characteristics of pediatric kidney transplant recipients, particularly those factors that may influence their care throughout their lives. We also discuss the risks associated with the transition from pediatric- to adult-oriented care and provide some suggestions to optimize transition to adult-oriented transplant care and long-term outcomes.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hey Rim Jung ◽  
Mi Joung Kim ◽  
Yu-Mee Wee ◽  
Jee Yeon Kim ◽  
Monica Young Choi ◽  
...  

Abstract Little is known about the characteristics and clinical implications of specific subsets of intragraft natural killer (NK) cells in kidney transplant recipients. We analyzed 39 for-cause renal transplant biopsies performed at our center from May 2015 to July 2017. According to histopathologic reports, 8 patients (20.5%) had no rejection (NR), 11 (28.2%) had T cell-mediated rejections (TCMR) only, and 20 (51.3%) had antibody-mediated rejection (ABMR). NK cells were defined as CD3–CD56+ lymphocytes that are positive for CD57, CD49b, NKG2A, or KIR. The density of NK cells was significantly higher in the ABMR group (2.57 ± 2.58/mm2) than in the NR (0.12 ± 0.22/mm2) or the TCMR (0.25 ± 0.34/mm2) group (P = 0.002). Notably, CD56+CD57+ infiltrates (2.16 ± 1.89) were the most frequently observed compared with CD56+CD49b+ (0.05 ± 0.13), CD56+NKG2A+ (0.21 ± 0.69), and CD56+KIR+ (0.15 ± 0.42) cells in the ABMR group (P < 0.001). Death-censored graft failure was significantly higher in patients with NK cell infiltration than those without (Log-rank test, P = 0.025). In conclusion, CD56+CD57+ infiltrates are a major subset of NK cells in kidney transplant recipients with ABMR and NK cell infiltration is significantly associated with graft failure post-transplant.


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