{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T11:04:03Z","timestamp":1767956643694,"version":"3.49.0"},"reference-count":17,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T00:00:00Z","timestamp":1767916800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Life"],"abstract":"<jats:p>Metabolic acidosis is common after kidney transplantation and has been linked to adverse renal outcomes. However, its relationship with histological injury in kidney allografts remains poorly characterized. We aimed to explore the association between metabolic acidosis and histopathological features in kidney allograft biopsies. This single-center, cross-sectional observational study included 63 adult kidney transplant recipients who underwent clinically indicated allograft biopsies. Metabolic acidosis was defined as a serum bicarbonate level &lt; 22 mmol\/L at the time of biopsy. Histological lesions were assessed according to the Banff classification. Lesion severity was evaluated using descriptive statistics, nonparametric comparisons, ordinal logistic regression, and multivariable logistic regression models adjusted for renal function, proteinuria, and time from transplantation. Sensitivity analyses additionally adjusted for hemoglobin and donor-related variables. Patients with metabolic acidosis exhibited numerically higher severity scores for both acute inflammatory lesions and chronic histological changes, including total inflammation and interstitial fibrosis\/tubular atrophy (IFTA). Across ordinal analyses and multivariable regression models, consistent directional trends toward a greater histological injury burden were observed among acidotic patients; however, none of these associations reached statistical significance, and confidence intervals were wide. Sensitivity analyses yielded directionally consistent effect estimates. In this biopsy-based analysis, metabolic acidosis showed consistent directional trends toward a higher burden of inflammatory and chronic histological lesions, although these findings did not reach statistical significance.<\/jats:p>","DOI":"10.3390\/life16010097","type":"journal-article","created":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T09:25:02Z","timestamp":1767950702000},"page":"97","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Histological Features of Kidney Allograft Biopsies According to Metabolic Acidosis Status: A Biopsy-Based Single-Center Observational Study"],"prefix":"10.3390","volume":"16","author":[{"given":"Lucian","family":"Siriteanu","sequence":"first","affiliation":[{"name":"Department of Nephrology, Grigore T. Popa University of Medicine and Pharmacy, 700115 Ia\u0219i, Romania"},{"name":"Clinical Hospital \u201cDr. C. I. Parhon\u201d, 700503 Ia\u0219i, Romania"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andreea Simona","family":"Covic","sequence":"additional","affiliation":[{"name":"Department of Nephrology, Grigore T. Popa University of Medicine and Pharmacy, 700115 Ia\u0219i, Romania"},{"name":"Clinical Hospital \u201cDr. C. I. Parhon\u201d, 700503 Ia\u0219i, Romania"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"C\u0103lin","family":"Namolovan","sequence":"additional","affiliation":[{"name":"Clinical Hospital \u201cDr. C. I. Parhon\u201d, 700503 Ia\u0219i, Romania"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mihai","family":"Onofriescu","sequence":"additional","affiliation":[{"name":"Department of Nephrology, Grigore T. Popa University of Medicine and Pharmacy, 700115 Ia\u0219i, Romania"},{"name":"Clinical Hospital \u201cDr. C. I. Parhon\u201d, 700503 Ia\u0219i, Romania"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8248-216X","authenticated-orcid":false,"given":"Simona Mihaela","family":"Hoga\u0219","sequence":"additional","affiliation":[{"name":"Department of Nephrology, Grigore T. Popa University of Medicine and Pharmacy, 700115 Ia\u0219i, Romania"},{"name":"Clinical Hospital \u201cDr. C. I. Parhon\u201d, 700503 Ia\u0219i, Romania"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lumini\u021ba","family":"Voroneanu","sequence":"additional","affiliation":[{"name":"Department of Nephrology, Grigore T. Popa University of Medicine and Pharmacy, 700115 Ia\u0219i, Romania"},{"name":"Clinical Hospital \u201cDr. C. I. Parhon\u201d, 700503 Ia\u0219i, Romania"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Irina-Draga","family":"C\u0103runtu","sequence":"additional","affiliation":[{"name":"Department of Nephrology, Grigore T. Popa University of Medicine and Pharmacy, 700115 Ia\u0219i, Romania"},{"name":"Clinical Hospital \u201cDr. C. I. Parhon\u201d, 700503 Ia\u0219i, Romania"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1297-0675","authenticated-orcid":false,"given":"Mehmet","family":"Kanbay","sequence":"additional","affiliation":[{"name":"Department of Medicine, Division of Nephrology, Koc University School of Medicine, Istanbul 34450, Turkey"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Adrian","family":"Covic","sequence":"additional","affiliation":[{"name":"Department of Nephrology, Grigore T. Popa University of Medicine and Pharmacy, 700115 Ia\u0219i, Romania"},{"name":"Clinical Hospital \u201cDr. C. I. Parhon\u201d, 700503 Ia\u0219i, Romania"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1684","DOI":"10.1016\/j.ekir.2024.04.007","article-title":"Metabolic acidosis is associated with an accelerated decline of allograft function in pediatric kidney transplantation","volume":"9","author":"Prytula","year":"2024","journal-title":"Kidney Int. Rep."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1886","DOI":"10.1681\/ASN.2016070793","article-title":"Metabolic acidosis and long-term clinical outcomes in kidney transplant recipients","volume":"28","author":"Park","year":"2017","journal-title":"J. Am. Soc. Nephrol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1016\/S0140-6736(22)02606-X","article-title":"Sodium bicarbonate for kidney transplant recipients with metabolic acidosis: A multicentre, randomized, single-blind, placebo-controlled, phase 3 trial","volume":"401","author":"Mohebbi","year":"2023","journal-title":"Lancet"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1806","DOI":"10.1093\/ndt\/gfab210","article-title":"Acidosis and alkali therapy in kidney transplant patients are associated with transcriptional changes and altered abundance of genes involved in cell metabolism and acid\u2013base balance","volume":"36","author":"Wiegand","year":"2021","journal-title":"Nephrol. Dial. Transplant."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"352","DOI":"10.7326\/0003-4819-79-3-352","article-title":"Renal tubular acidosis after kidney transplantation: Natural history and significance","volume":"79","author":"Wilson","year":"1973","journal-title":"Ann. Intern. Med."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"126","DOI":"10.1053\/ajkd.2003.50063","article-title":"Severe renal tubular acidosis in a renal transplant recipient with repeated acute rejections and chronic allograft nephropathy","volume":"41","author":"Cho","year":"2003","journal-title":"Am. J. Kidney Dis."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"e14648","DOI":"10.1111\/ctr.14648","article-title":"Increased intrarenal post\u2010glomerular blood flow is a key condition for the development of calcineurin inhibitor\u2010induced renal tubular acidosis in kidney transplant recipients","volume":"36","author":"Kaneko","year":"2022","journal-title":"Clin. Trans."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"702","DOI":"10.1159\/000508476","article-title":"Is metabolic acidosis a novel risk factor for long-term graft survival in patients after kidney transplantation?","volume":"45","author":"Gojowy","year":"2020","journal-title":"Kidney Blood Press. Res."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"619","DOI":"10.1007\/s40620-021-01197-6","article-title":"Association of serum bicarbonate with graft survival and mortality in kidney transplant recipients","volume":"35","author":"Wiegand","year":"2021","journal-title":"J. Nephrol."},{"key":"ref_10","first-page":"100418","article-title":"Serum bicarbonate and graft and patient outcomes among kidney transplant recipients: A retrospective cohort study evaluating changes in serum bicarbonate over time","volume":"5","author":"Mathur","year":"2022","journal-title":"Kidney Med."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"792","DOI":"10.1159\/000510158","article-title":"Causes and consequences of metabolic acidosis in patients after kidney transplantation","volume":"45","author":"Ritter","year":"2020","journal-title":"Kidney Blood Press. Res."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1080\/00325481.2019.1592360","article-title":"Hyperchloremic metabolic acidosis in the kidney transplant patient","volume":"131","author":"Azevedo","year":"2019","journal-title":"Postgrad. 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Sci., 25.","DOI":"10.3390\/ijms25105187"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"574","DOI":"10.1097\/00007890-201407151-01934","article-title":"Factors predisposing to metabolic acidosis in kidney transplant patients","volume":"98","author":"Adamczak","year":"2014","journal-title":"Transplantation"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"e150971","DOI":"10.1172\/jci.insight.161783","article-title":"Impaired fatty acid metabolism perpetuates lipotoxicity during the transition to chronic kidney injury","volume":"7","author":"Rinaldi","year":"2022","journal-title":"JCI Insight"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"350","DOI":"10.1016\/j.ajt.2023.10.031","article-title":"The Banff 2022 Kidney Meeting Work Plan: Data-driven refinement of the Banff Classification for renal allografts","volume":"24","author":"Roufosse","year":"2024","journal-title":"Am. J. Transplant."}],"container-title":["Life"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2075-1729\/16\/1\/97\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T09:31:56Z","timestamp":1767951116000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2075-1729\/16\/1\/97"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,9]]},"references-count":17,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,1]]}},"alternative-id":["life16010097"],"URL":"https:\/\/doi.org\/10.3390\/life16010097","relation":{},"ISSN":["2075-1729"],"issn-type":[{"value":"2075-1729","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,9]]}}}