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Kuhn C, Mohebbi N, Ritter A. Metabolic acidosis in chronic kidney disease: mere consequence or also culprit? Pflugers Arch 2024; 476:579-592. [PMID: 38279993 PMCID: PMC11006741 DOI: 10.1007/s00424-024-02912-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 01/29/2024]
Abstract
Metabolic acidosis is a frequent complication in non-transplant chronic kidney disease (CKD) and after kidney transplantation. It occurs when net endogenous acid production exceeds net acid excretion. While nephron loss with reduced ammoniagenesis is the main cause of acid retention in non-transplant CKD patients, additional pathophysiological mechanisms are likely inflicted in kidney transplant recipients. Functional tubular damage by calcineurin inhibitors seems to play a key role causing renal tubular acidosis. Notably, experimental and clinical studies over the past decades have provided evidence that metabolic acidosis may not only be a consequence of CKD but also a driver of disease. In metabolic acidosis, activation of hormonal systems and the complement system resulting in fibrosis have been described. Further studies of changes in renal metabolism will likely contribute to a deeper understanding of the pathophysiology of metabolic acidosis in CKD. While alkali supplementation in case of reduced serum bicarbonate < 22 mmol/l has been endorsed by CKD guidelines for many years to slow renal functional decline, among other considerations, beneficial effects and thresholds for treatment have lately been under intense debate. This review article discusses this topic in light of the most recent results of trials assessing the efficacy of dietary and pharmacological interventions in CKD and kidney transplant patients.
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Affiliation(s)
- Christian Kuhn
- Clinic for Nephrology and Transplantation Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland
| | | | - Alexander Ritter
- Clinic for Nephrology and Transplantation Medicine, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.
- Clinic for Nephrology, University Hospital Zurich, Zurich, Switzerland.
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2
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Park M, Cave G, Freebairn R. Metabolic acidosis in anaesthesia and critical care. BJA Educ 2024; 24:91-99. [PMID: 38375495 PMCID: PMC10874758 DOI: 10.1016/j.bjae.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2023] [Indexed: 02/21/2024] Open
Affiliation(s)
- M.A.J. Park
- Te Matau a Maui Hawke's Bay, Health New Zealand, Hastings, New Zealand
| | - G. Cave
- Te Matau a Maui Hawke's Bay, Health New Zealand, Hastings, New Zealand
| | - R.C. Freebairn
- Te Matau a Maui Hawke's Bay, Health New Zealand, Hastings, New Zealand
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3
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Medeiros H, Lima PH, Junior VS, Souza DA, Pinheiro AM, Martins RR, A H Costa KM, Junior JHD, Medeiros PJ, Da Silva WA. A Comparison Between Saline and Balanced Solutions in Kidney Transplants: A Randomized Clinical Trial. Cureus 2023; 15:e49813. [PMID: 38164322 PMCID: PMC10758014 DOI: 10.7759/cureus.49813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2023] [Indexed: 01/03/2024] Open
Abstract
Objective This study aimed to investigate the impact of different types of intravenous fluids - normal saline (NS), lactated Ringer's solution (LR), and PlasmaLyte (PL) - on the acid-base balance and electrolyte concentration following kidney transplant, a common procedure for patients with end-stage renal disease (ESRD). Methodology A randomized controlled trial design was employed, wherein the primary parameters analyzed were postoperative pH and serum potassium levels. Postoperative concentrations of serum bicarbonate, sodium, chloride, and creatinine, as well as graft functionality, were assessed as secondary outcomes. These measurements were performed at the start and end of surgery, as well as 24 and 72 hours postoperatively. Results A total of 53 patients were included in the study and randomized into three cohorts: NS, LR, and PL, each of which showed comparability in terms of demographic and transplantation specifics. Notably, patients in the NS group exhibited a more significant decrease in pH (NS group: 7.285 ±0.098, LR group: 7.324 ±0.075, PL group: 7.7338 ±0.059) and bicarbonate levels (17.0 ±4.2, 20.9 ±2.8, 20.0 ±4.5) post 24 hours after the operation and displayed a similar pattern immediately after the surgery. However, there were no discernible differences in potassium (p=0.460), sodium (p=0.681), and chloride (p=0.321) levels across the groups. Furthermore, the study did not observe any significant differences in postoperative graft functionality. Conclusion The use of NS as the intraoperative fluid of choice led to lower pH and bicarbonate levels following kidney transplant, as compared to LR and PL. However, these results did not correlate with improvements in graft functionality.
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Affiliation(s)
- Heitor Medeiros
- Department of Anesthesiology, Hospital Universitário Onofre Lopes, Natal, BRA
| | - Paulo H Lima
- Department of Anesthesiology, Hospital Universitário Onofre Lopes, Natal, BRA
| | - Vital S Junior
- Department of Anesthesiology, Hospital Universitário Onofre Lopes, Natal, BRA
| | - Diego A Souza
- Department of Anesthesiology, Hospital Universitário Onofre Lopes, Natal, BRA
| | - Aline M Pinheiro
- Department of Anesthesiology, Hospital Universitário Onofre Lopes, Natal, BRA
| | - Rand R Martins
- Graduate Program of Pharmaceutical Assistance, Universidade Federal do Rio Grande do Norte, Natal, BRA
| | - Kellen M A H Costa
- Department of Nephrology, Universidade Federal do Rio Grande do Norte, Natal, BRA
| | | | - Paulo J Medeiros
- Department of Urology, Hospital Universitário Onofre Lopes, Natal, BRA
| | - Wallace A Da Silva
- Department of Anesthesiology, Hospital Universitário Onofre Lopes, Natal, BRA
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4
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Kilduff S, Hayde N, Viswanathan S, Reidy K, Abramowitz MK. Metabolic acidosis in pediatric kidney transplant recipients. Pediatr Nephrol 2023; 38:4165-4173. [PMID: 37422606 DOI: 10.1007/s00467-023-06072-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 06/22/2023] [Accepted: 06/22/2023] [Indexed: 07/10/2023]
Abstract
BACKGROUND Metabolic acidosis is a risk factor for faster kidney function decline in chronic kidney disease (CKD) and in adult kidney transplant recipients (KTRs). We hypothesized that metabolic acidosis would be highly prevalent and associated with worse allograft function in pediatric KTRs. METHODS Pediatric KTRs at Montefiore Medical Center from 2010 to 2018 were included. Metabolic acidosis was defined as serum bicarbonate < 22 mEq/L or receiving alkali therapy. Regression models were adjusted for demographic factors and donor/recipient characteristics. RESULTS Sixty-three patients were identified with a median age at transplant of 10.5 (interquartile range (IQR) 4.4-15.2) years and post-transplant follow-up of 3 (IQR 1-5) years. Baseline serum bicarbonate was 21.7 ± 2.4 mEq/L, serum bicarbonate < 22 mEq/L was present in 28 (44%), and 44% of all patients were receiving alkali therapy. The prevalence of acidosis ranged from 58 to 70% during the first year of follow-up. At baseline, each 1-year higher age at transplant and every 10 ml/min/1.73 m2 higher eGFR were associated with 0.16 mEq/L (95% CI: 0.03-0.3) and 0.24 mEq/L (95% CI: 0.01-0.5) higher serum bicarbonate, respectively. Older age at transplant was associated with lower odds of acidosis (OR: 0.84; 95% CI: 0.72-0.97). During follow-up, metabolic acidosis was independently associated with 8.2 ml/min/1.73 m2 (95% CI 4.4-12) lower eGFR compared to not having acidosis; furthermore, eGFR was significantly lower among KTRs with unresolved acidosis compared with resolved acidosis. CONCLUSIONS Among pediatric KTRs, metabolic acidosis was highly prevalent in the first year post-transplantation and was associated with lower eGFR during follow-up. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Stella Kilduff
- The Children's Hospital at Montefiore/Einstein, Bronx, NY, USA.
- Albert Einstein College of Medicine, Bronx, NY, USA.
| | - Nicole Hayde
- The Children's Hospital at Montefiore/Einstein, Bronx, NY, USA
| | | | - Kimberly Reidy
- The Children's Hospital at Montefiore/Einstein, Bronx, NY, USA
| | - Matthew K Abramowitz
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY, USA
- Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, USA
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5
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Kotwal N, Bansal N, Muthukrishnan J, Verma V. Transplant endocrinology. Med J Armed Forces India 2023; 79:651-656. [PMID: 37981924 PMCID: PMC10654368 DOI: 10.1016/j.mjafi.2023.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 08/27/2023] [Indexed: 11/21/2023] Open
Abstract
Solid organ transplants and stem cell transplants are becoming more common but a significant proportion of patients are still on waiting lists, awaiting transplants. When endocrinologists treat transplant recipients who have underlying endocrine problems, which might include endocrine emergencies, there are special clinical care considerations to be aware of. The stage of the transplant (pre-transplant, early post-transplant, and chronic post-transplant) must be taken into account. Additionally, it's crucial to be knowledgeable about immunosuppressive medications, their typical adverse effects and drug interactions. The review article addresses a number of endocrine and metabolic abnormalities that are reported after transplantation.
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Affiliation(s)
- Narendra Kotwal
- Director & Commandant, Armed Forces Medical College, Pune, India
| | - Naresh Bansal
- Senior Adviser (Medicine) & Endocrinologist, Command Hospital (Southern Command), Pune, India
| | - J. Muthukrishnan
- Professor & Head, Department of Internal Medicine, Armed Forces Medical College, Pune, India
| | - Vishesh Verma
- Professor, Department of Internal Medicine, Armed Forces Medical College, Pune, India
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Mohebbi N, Ritter A. Bicarbonate ineffectiveness for kidney transplant - Authors' reply. Lancet 2023; 402:1528. [PMID: 37898532 DOI: 10.1016/s0140-6736(23)01624-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 08/02/2023] [Indexed: 10/30/2023]
Affiliation(s)
- Nilufar Mohebbi
- Division of Nephrology, University Hospital, Zurich 8091, Switzerland.
| | - Alexander Ritter
- Division of Nephrology, University Hospital, Zurich 8091, Switzerland
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7
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Wagner CA, Unwin R, Lopez-Garcia SC, Kleta R, Bockenhauer D, Walsh S. The pathophysiology of distal renal tubular acidosis. Nat Rev Nephrol 2023; 19:384-400. [PMID: 37016093 DOI: 10.1038/s41581-023-00699-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2023] [Indexed: 04/06/2023]
Abstract
The kidneys have a central role in the control of acid-base homeostasis owing to bicarbonate reabsorption and production of ammonia and ammonium in the proximal tubule and active acid secretion along the collecting duct. Impaired acid excretion by the collecting duct system causes distal renal tubular acidosis (dRTA), which is characterized by the failure to acidify urine below pH 5.5. This defect originates from reduced function of acid-secretory type A intercalated cells. Inherited forms of dRTA are caused by variants in SLC4A1, ATP6V1B1, ATP6V0A4, FOXI1, WDR72 and probably in other genes that are yet to be discovered. Inheritance of dRTA follows autosomal-dominant and -recessive patterns. Acquired forms of dRTA are caused by various types of autoimmune diseases or adverse effects of some drugs. Incomplete dRTA is frequently found in patients with and without kidney stone disease. These patients fail to appropriately acidify their urine when challenged, suggesting that incomplete dRTA may represent an intermediate state in the spectrum of the ability to excrete acids. Unrecognized or insufficiently treated dRTA can cause rickets and failure to thrive in children, osteomalacia in adults, nephrolithiasis and nephrocalcinosis. Electrolyte disorders are also often present and poorly controlled dRTA can increase the risk of developing chronic kidney disease.
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Affiliation(s)
- Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland.
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK.
| | - Robert Unwin
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
| | - Sergio C Lopez-Garcia
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
- Department of Paediatric Nephrology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Robert Kleta
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
| | - Detlef Bockenhauer
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
- Department of Paediatric Nephrology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Stephen Walsh
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
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Andrian T, Siriteanu L, Covic AS, Ipate CA, Miron A, Morosanu C, Caruntu ID, Covic A. Non-Traditional Non-Immunological Risk Factors for Kidney Allograft Loss-Opinion. J Clin Med 2023; 12:jcm12062364. [PMID: 36983364 PMCID: PMC10051358 DOI: 10.3390/jcm12062364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/16/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
Rates of late allograft loss have improved slowly in the last decades. Well described traditional risk factors that influence allograft survival include cardiovascular events, rejection, infections and post-transplant neoplasia. Here, we critically evaluate the influence of several non-immunological, non-traditional risk factors and describe their impact on allograft survival and cardiovascular health of kidney transplant recipients. We assessed the following risk factors: arterial stiffness, persistent arteriovenous access, mineral bone disease, immunosuppressive drugs residual levels variability, hypomagnesemia, glomerular pathological alterations not included in Banff criteria, persistent inflammation and metabolic acidosis.
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Affiliation(s)
- Titus Andrian
- Nephrology Clinic, Dialysis and Renal Transplant Center, C. I. Parhon University Hospital, 700503 Iasi, Romania
- Department of Internal Medicine, 'Grigore T. Popa' University of Medicine, 700115 Iasi, Romania
| | - Lucian Siriteanu
- Nephrology Clinic, Dialysis and Renal Transplant Center, C. I. Parhon University Hospital, 700503 Iasi, Romania
- Department of Internal Medicine, 'Grigore T. Popa' University of Medicine, 700115 Iasi, Romania
| | - Andreea Simona Covic
- Nephrology Clinic, Dialysis and Renal Transplant Center, C. I. Parhon University Hospital, 700503 Iasi, Romania
- Department of Internal Medicine, 'Grigore T. Popa' University of Medicine, 700115 Iasi, Romania
| | - Cristina Alexandra Ipate
- Nephrology Clinic, Dialysis and Renal Transplant Center, C. I. Parhon University Hospital, 700503 Iasi, Romania
| | - Adelina Miron
- Nephrology Clinic, Dialysis and Renal Transplant Center, C. I. Parhon University Hospital, 700503 Iasi, Romania
- Department of Internal Medicine, 'Grigore T. Popa' University of Medicine, 700115 Iasi, Romania
| | - Corneliu Morosanu
- Nephrology Clinic, Dialysis and Renal Transplant Center, C. I. Parhon University Hospital, 700503 Iasi, Romania
| | - Irina-Draga Caruntu
- Department of Internal Medicine, 'Grigore T. Popa' University of Medicine, 700115 Iasi, Romania
| | - Adrian Covic
- Nephrology Clinic, Dialysis and Renal Transplant Center, C. I. Parhon University Hospital, 700503 Iasi, Romania
- Department of Internal Medicine, 'Grigore T. Popa' University of Medicine, 700115 Iasi, Romania
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9
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Mohebbi N, Ritter A, Wiegand A, Graf N, Dahdal S, Sidler D, Arampatzis S, Hadaya K, Mueller TF, Wagner CA, Wüthrich RP. Sodium bicarbonate for kidney transplant recipients with metabolic acidosis in Switzerland: a multicentre, randomised, single-blind, placebo-controlled, phase 3 trial. Lancet 2023; 401:557-567. [PMID: 36708734 DOI: 10.1016/s0140-6736(22)02606-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 11/17/2022] [Accepted: 12/13/2022] [Indexed: 01/27/2023]
Abstract
BACKGROUND Metabolic acidosis is common in kidney transplant recipients and is associated with declining graft function. Sodium bicarbonate treatment effectively corrects metabolic acidosis, but no prospective studies have examined its effect on graft function. Therefore, we aimed to test whether sodium bicarbonate treatment would preserve graft function and slow the progression of estimated glomerular filtration rate (GFR) decline in kidney transplant recipients. METHODS The Preserve-Transplant Study was a multicentre, randomised, single-blind, placebo-controlled, phase 3 trial at three University Hospitals in Switzerland (Zurich, Bern, and Geneva), which recruited adult (aged ≥18 years) male and female long-term kidney transplant recipients if they had undergone transplantation more than 1 year ago. Key inclusion criteria were an estimated GFR between 15 mL/min per 1·73 m2 and 89 mL/min per 1·73 m2, stable allograft function in the last 6 months before study inclusion (<15% change in serum creatinine), and a serum bicarbonate of 22 mmol/L or less. We randomly assigned patients (1:1) to either oral sodium bicarbonate 1·5-4·5 g per day or matching placebo using web-based data management software. Randomisation was stratified by study centre and gender using a permuted block design to guarantee balanced allocation. We did multi-block randomisation with variable block sizes of two and four. Treatment duration was 2 years. Acid-resistant soft gelatine capsules of 500 mg sodium bicarbonate or matching 500 mg placebo capsules were given at an initial dose of 500 mg (if bodyweight was <70 kg) or 1000 mg (if bodyweight was ≥70 kg) three times daily. The primary endpoint was the estimated GFR slope over the 24-month treatment phase. The primary efficacy analyses were applied to a modified intention-to-treat population that comprised all randomly assigned participants who had a baseline visit. The safety population comprised all participants who received at least one dose of study drug. The trial is registered with ClinicalTrials.gov, NCT03102996. FINDINGS Between June 12, 2017, and July 10, 2019, 1114 kidney transplant recipients with metabolic acidosis were assessed for trial eligibility. 872 patients were excluded and 242 were randomly assigned to the study groups (122 [50%] to the placebo group and 120 [50%] to the sodium bicarbonate group). After secondary exclusion of two patients, 240 patients were included in the intention-to-treat analysis. The calculated yearly estimated GFR slopes over the 2-year treatment period were a median -0·722 mL/min per 1·73 m2 (IQR -4·081 to 1·440) and mean -1·862 mL/min per 1·73 m2 (SD 6·344) per year in the placebo group versus median -1·413 mL/min per 1·73 m2 (IQR -4·503 to 1·139) and mean -1·830 mL/min per 1·73 m2 (SD 6·233) per year in the sodium bicarbonate group (Wilcoxon rank sum test p=0·51; Welch t-test p=0·97). The mean difference was 0·032 mL/min per 1·73 m2 per year (95% CI -1·644 to 1·707). There were no significant differences in estimated GFR slopes in a subgroup analysis and a sensitivity analysis confirmed the primary analysis. Although the estimated GFR slope did not show a significant difference between the treatment groups, treatment with sodium bicarbonate effectively corrected metabolic acidosis by increasing serum bicarbonate from 21·3 mmol/L (SD 2·6) to 23·0 mmol/L (2·7) and blood pH from 7·37 (SD 0·06) to 7·39 (0·04) over the 2-year treatment period. Adverse events and serious adverse events were similar in both groups. Three study participants died. In the placebo group, one (1%) patient died from acute respiratory distress syndrome due to SARS-CoV-2 and one (1%) from cardiac arrest after severe dehydration following diarrhoea with hypotension, acute kidney injury, and metabolic acidosis. In the sodium bicarbonate group, one (1%) patient had sudden cardiac death. INTERPRETATION In adult kidney transplant recipients, correction of metabolic acidosis by treatment with sodium bicarbonate over 2 years did not affect the decline in estimated GFR. Thus, treatment with sodium bicarbonate should not be generally recommended to preserve estimated GFR (a surrogate marker for graft function) in kidney transplant recipients with chronic kidney disease who have metabolic acidosis. FUNDING Swiss National Science Foundation.
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Affiliation(s)
- Nilufar Mohebbi
- Division of Nephrology, University Hospital, Zurich, Switzerland.
| | - Alexander Ritter
- Division of Nephrology, University Hospital, Zurich, Switzerland
| | - Anna Wiegand
- Division of Nephrology, University Hospital, Zurich, Switzerland
| | | | - Suzan Dahdal
- Division of Nephrology and Hypertension, Inselspital, Bern, Switzerland
| | - Daniel Sidler
- Division of Nephrology and Hypertension, Inselspital, Bern, Switzerland
| | | | - Karine Hadaya
- Division of Nephrology and Hypertension, University Hospital, Geneva, Switzerland
| | - Thomas F Mueller
- Division of Nephrology, University Hospital, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
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10
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Circulating Metabolites in Relation to the Kidney Allograft Function in Posttransplant Patients. Metabolites 2022; 12:metabo12070661. [PMID: 35888785 PMCID: PMC9318187 DOI: 10.3390/metabo12070661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/14/2022] [Accepted: 07/14/2022] [Indexed: 12/05/2022] Open
Abstract
End-stage kidney disease is preferably treated by kidney transplantation. The suboptimal function of the allograft often results in misbalances in kidney-controlled processes and requires long-term monitoring of allograft function and viability. As the kidneys are organs with a very high metabolomic rate, a metabolomics approach is suitable to describe systematic changes in post-transplant patients and has great potential for monitoring allograft function, which has not been described yet. In this study, we used blood plasma samples from 55 patients after primary kidney transplantation identically treated with immunosuppressants with follow-up 50 months in the mean after surgery and evaluated relative levels of basal plasma metabolites detectable by NMR spectroscopy. We were looking for the correlations between circulating metabolites levels and allograft performance and allograft rejection features. Our results imply a quantitative relationship between restricted renal function, insufficient hydroxylation of phenylalanine to tyrosine, lowered renal glutamine utilization, shifted nitrogen balance, and other alterations that are not related exclusively to the metabolism of the kidney. No link between allograft function and energy metabolism can be concluded, as no changes were found for glucose, glycolytic intermediates, and 3-hydroxybutyrate as a ketone body representative. The observed changes are to be seen as a superposition of changes in the comprehensive inter-organ metabolic exchange, when the restricted function of one organ may induce compensatory effects or cause secondary alterations. Particular differences in plasma metabolite levels in patients with acute cellular and antibody-mediated allograft rejection were considered rather to be related to the loss of kidney function than to the molecular mechanism of graft rejection since they largely follow the alterations observed by restricted allograft function. In the end, we showed using a simple mathematical model, multilinear regression, that the basal plasmatic metabolites correlated with allograft function expressed by the level of glomerular filtration rate (with creatinine: p-value = 4.0 × 10−26 and r = 0.94, without creatinine: p-value = 3.2 × 10−22 and r = 0.91) make the noninvasive estimation of the allograft function feasible.
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11
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Kaneko S, Usui J, Takahashi K, Oda T, Yamagata K. Increased intrarenal post-glomerular blood flow is a key condition for the development of calcineurin inhibitor-induced renal tubular acidosis in kidney transplant recipients. Clin Transplant 2022; 36:e14648. [PMID: 35293652 DOI: 10.1111/ctr.14648] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 03/04/2022] [Accepted: 03/08/2022] [Indexed: 12/24/2022]
Abstract
BACKGROUND Hyperchloremic metabolic acidosis (HCMA) from renal tubular acidosis (RTA) is common in kidney transplant (KT) recipients. Calcineurin inhibitors (CNIs) are a potential cause of RTA, and whether HCMA is a determinant of poor graft prognosis is controversial. METHODS The subjects were living-donor KT recipients (LDKTRs, n = 47) and matched donors (n = 43). All cases of rejection, extrarenal causes, and respiratory disorders were excluded. HCMA was defined as having a [Na+] - [Cl-] value of ≤ 34 or starting alkalization. We determined the potential causes of HCMA in LDKTRs at 3 months (m) and 1 year (y) post-KT. We examined renal hemodynamic parameters in 26 LDKTRs at 1 y post-KT: namely, glomerular filtration rate (GFR), renal plasma flow (RPF), filtration fraction (FF; GFR/RPF) and pre-/post-glomerular vascular resistance (pre-/postVR). RESULTS The HCMA incidence in the 3-m post-KT LDKTR group was higher than that of the donors (51.0% vs. 6.9%, p<0.001, adjusted odds ratio: 6.7-15.7). Among adjusted factors, the most dominant HCMA contributor was low hemoglobin concentration (Hb ≤12 g/dL). Compared to non-HCMA cases, HCMA patients had low FF and low post-VR (p = 0.008, 0.003, respectively) suggesting increased intrarenal post-glomerular blood flow. The high pathological score of alternative arteriolar hyalinosis (aah) ≥2 was a significant HCMA risk. The tacrolimus trough level was not high in HCMA but was significantly high in HCMA in the low post-VR setting (p = 0.002). CONCLUSION Among LDKTRs, low hemoglobin level is an important contributor to the manifestation of HCMA in the induction period, and increased intrarenal post-glomerular blood flow is a key condition for the development of CNI-induced RTA. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Shuzo Kaneko
- Department of Nephrology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.,Department of Nephrology, Itabashi Chuo Medical Center, Itabashi, Tokyo, Japan
| | - Joichi Usui
- Department of Nephrology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Kazuhiro Takahashi
- Department of Gastroenterological and Hepatobiliary Surgery and Organ Transplantation, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Tatsuya Oda
- Department of Gastroenterological and Hepatobiliary Surgery and Organ Transplantation, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Kunihiro Yamagata
- Department of Nephrology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
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12
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Imenez Silva PH, Unwin R, Hoorn EJ, Ortiz A, Trepiccione F, Nielsen R, Pesic V, Hafez G, Fouque D, Massy ZA, De Zeeuw CI, Capasso G, Wagner CA. Acidosis, cognitive dysfunction and motor impairments in patients with kidney disease. Nephrol Dial Transplant 2021; 37:ii4-ii12. [PMID: 34718761 PMCID: PMC8713149 DOI: 10.1093/ndt/gfab216] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Indexed: 12/20/2022] Open
Abstract
Metabolic acidosis, defined as a plasma or serum bicarbonate concentration <22 mmol/L, is a frequent consequence of chronic kidney disease (CKD) and occurs in ~10–30% of patients with advanced stages of CKD. Likewise, in patients with a kidney transplant, prevalence rates of metabolic acidosis range from 20% to 50%. CKD has recently been associated with cognitive dysfunction, including mild cognitive impairment with memory and attention deficits, reduced executive functions and morphological damage detectable with imaging. Also, impaired motor functions and loss of muscle strength are often found in patients with advanced CKD, which in part may be attributed to altered central nervous system (CNS) functions. While the exact mechanisms of how CKD may cause cognitive dysfunction and reduced motor functions are still debated, recent data point towards the possibility that acidosis is one modifiable contributor to cognitive dysfunction. This review summarizes recent evidence for an association between acidosis and cognitive dysfunction in patients with CKD and discusses potential mechanisms by which acidosis may impact CNS functions. The review also identifies important open questions to be answered to improve prevention and therapy of cognitive dysfunction in the setting of metabolic acidosis in patients with CKD.
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Affiliation(s)
- Pedro H Imenez Silva
- Institute of Physiology, University of Zurich, Zürich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Zürich, Switzerland
| | - Robert Unwin
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
| | - Ewout J Hoorn
- Department of Internal Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Alberto Ortiz
- Department of Nephrology and Hypertension, IIS-Fundacion Jimenez Diaz, Universidad Autonoma de Madrid, Madrid, Spain
| | - Francesco Trepiccione
- Biogem Institute of Molecular Biology and Genetics, Ariano Irpino, Italy.,Department of Translational Medical Sciences, University of Campania "Luigi Vanvitelli," Naples, Italy
| | - Rikke Nielsen
- Department of Biomedicine-Anatomy, University of Aarhus, Aarhus, Denmark
| | - Vesna Pesic
- Department of Physiology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Gaye Hafez
- Department of Pharmacology, Faculty of Pharmacy, Altinbas University, Istanbul, Turkey
| | - Denis Fouque
- CarMeN, INSERM 1060, Université Claude Bernard Lyon 1, Lyon, France.,Service de Néphrologie, Lyon-Sud Hospital, Pierre-Bénite, France
| | - Ziad A Massy
- Department of Nephrology, Ambroise Paré University Hospital, Assistance Publique Hôpitaux de Paris, Boulogne-Billancourt, France.,Centre de Recherche en Epidémiologie et Santé des Populations, Institut National de la Santé et de la Recherche Médicale U1018-Team 5, Université de Versailles Saint-Quentin-en-Yvelines, University Paris Saclay, Villejuif, France
| | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands.,Netherlands Institute for Neuroscience, Royal Dutch Academy of Art and Science, Amsterdam, The Netherlands
| | - Giovambattista Capasso
- Biogem Institute of Molecular Biology and Genetics, Ariano Irpino, Italy.,Department of Translational Medical Sciences, University of Campania "Luigi Vanvitelli," Naples, Italy
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zürich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Zürich, Switzerland
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13
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Tantisattamo E, Ho BT, Workeneh BT. Editorial: Metabolic Changes After Kidney Transplantation. Front Med (Lausanne) 2021; 8:709644. [PMID: 34307432 PMCID: PMC8297834 DOI: 10.3389/fmed.2021.709644] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 05/31/2021] [Indexed: 01/21/2023] Open
Affiliation(s)
- Ekamol Tantisattamo
- Harold Simmons Center for Kidney Disease Research and Epidemiology, Division of Nephrology, Hypertension and Kidney Transplantation, Department of Medicine, University of California, Irvine School of Medicine, Orange, CA, United States.,Nephrology Section, Department of Medicine, Tibor Rubin Veterans Affairs Medical Center, Veterans Affairs Long Beach Healthcare System, Long Beach, CA, United States.,Multi-Organ Transplant Center, Section of Nephrology, Department of Internal Medicine, William Beaumont Hospital, Oakland University William Beaumont School of Medicine, Royal Oak, MI, United States
| | - Bing T Ho
- Comprehensive Transplant Center, Division of Nephrology and Hypertension, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Biruh T Workeneh
- Section of Nephrology, University of Texas MD Anderson Cancer Center, Houston, TX, United States
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14
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Silva PHI, Wiegand A, Daryadel A, Russo G, Ritter A, Gaspert A, Wüthrich RP, Wagner CA, Mohebbi N. Acidosis and alkali therapy in patients with kidney transplant is associated with transcriptional changes and altered abundance of genes involved in cell metabolism and acid-base balance. Nephrol Dial Transplant 2021; 36:1806-1820. [PMID: 34240183 DOI: 10.1093/ndt/gfab210] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Metabolic acidosis occurs frequently in patients with kidney transplant and is associated with higher risk for and accelerated loss of graft function. To date, it is not known whether alkali therapy in these patients improves kidney function and whether acidosis and its therapy is associated with altered expression of proteins involved in renal acid-base metabolism. METHODS We collected retrospectively kidney biopsies from 22 patients. Of these patients, 9 had no acidosis, 9 had metabolic acidosis (plasma HCO3- < 22 mmol/l), and 4 had acidosis and received alkali therapy. We performed transcriptome analysis and immunohistochemistry for proteins involved in renal acid-base handling. RESULTS We found the expression of 40 transcripts significantly changed between kidneys from non-acidotic and acidotic patients. These genes are mostly involved in proximal tubule amino acid and lipid metabolism and energy homeostasis. Three transcripts were fully recovered by alkali therapy: the Kir4.2 K+-channel, an important regulator of proximal tubule HCO3--metabolism and transport, ACADSB and SHMT1, genes involved in beta-oxidation and methionine metabolism. Immunohistochemistry showed reduced staining for the proximal tubule NBCe1 HCO3- transporter in kidneys from acidotic patients that recovered with alkali therapy. In addition, the HCO3-exchanger pendrin was affected by acidosis and alkali therapy. CONCLUSIONS Metabolic acidosis in kidney transplant recipients is associated with alterations in the renal transcriptome that are partly restored by alkali therapy. Acid-base transport proteins mostly from proximal tubule were also affected by acidosis and alkali therapy suggesting that the downregulation of critical players contributes to metabolic acidosis in these patients.
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Affiliation(s)
- Pedro H Imenez Silva
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Switzerland
| | - Anna Wiegand
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Arezoo Daryadel
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Switzerland
| | - Giancarlo Russo
- Functional Genomics Center Zürich, University of Zürich and ETH Zürich, Zürich, Switzerland
| | - Alexander Ritter
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Ariana Gaspert
- Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Rudolf P Wüthrich
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Switzerland
| | - Nilufar Mohebbi
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
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