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Zhang Y, Liang Y, Xiang H, Li P, Zhan D, Ding D, Du S, Ding Y, Liu W, Qiu X, Feng H. Critical impact of pressure regulation on carbon dioxide biosynthesis. BIORESOURCE TECHNOLOGY 2024; 413:131445. [PMID: 39278365 DOI: 10.1016/j.biortech.2024.131445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2024] [Revised: 09/03/2024] [Accepted: 09/03/2024] [Indexed: 09/18/2024]
Abstract
Carbon dioxide (CO2) biosynthesis is a promising alternative to traditional chemical synthesis. However, its application in engineering is hampered by poor gas mass transfer rates. Pressurization is an effective method to enhance mass transfer and increase synthesis yield, although the underlying mechanisms remain unclear. This review examines the effects of high pressure on CO2 biosynthesis, elucidating the mechanisms behind yield enhancement from three perspectives: microbial physiological traits, gas mass transfer and synthetic pathways. The critical role of pressurization in improving microbial activity and gas transfer efficiency is emphasized, with particular attention to maintaining pressure within microbial tolerance limits to maximize yield without compromising cell structure integrity.
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Affiliation(s)
- Yanqing Zhang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, Zhejiang, China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou 310012, Zhejiang, China
| | - Yuxiang Liang
- College of Environment and Resources, College of Carbon Neutral, Zhejiang Agriculture and Forestry University, Hangzhou, Zhejiang 311300, China
| | - Hai Xiang
- College of Environment and Resources, College of Carbon Neutral, Zhejiang Agriculture and Forestry University, Hangzhou, Zhejiang 311300, China
| | - Pingli Li
- College of Environment and Resources, College of Carbon Neutral, Zhejiang Agriculture and Forestry University, Hangzhou, Zhejiang 311300, China
| | - Dongqing Zhan
- College of Environment and Resources, College of Carbon Neutral, Zhejiang Agriculture and Forestry University, Hangzhou, Zhejiang 311300, China
| | - Danna Ding
- College of Environment and Resources, College of Carbon Neutral, Zhejiang Agriculture and Forestry University, Hangzhou, Zhejiang 311300, China
| | - Shuangwei Du
- College of Environment and Resources, College of Carbon Neutral, Zhejiang Agriculture and Forestry University, Hangzhou, Zhejiang 311300, China
| | - Yangcheng Ding
- College of Environment and Resources, College of Carbon Neutral, Zhejiang Agriculture and Forestry University, Hangzhou, Zhejiang 311300, China
| | - Wen Liu
- College of Environment and Resources, College of Carbon Neutral, Zhejiang Agriculture and Forestry University, Hangzhou, Zhejiang 311300, China
| | - Xiawen Qiu
- College of Environment and Resources, College of Carbon Neutral, Zhejiang Agriculture and Forestry University, Hangzhou, Zhejiang 311300, China
| | - Huajun Feng
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018, Zhejiang, China; College of Environment and Resources, College of Carbon Neutral, Zhejiang Agriculture and Forestry University, Hangzhou, Zhejiang 311300, China; International Science and Technology Cooperation Platform for Low-Carbon Recycling of Waste and Green Development, Zhejiang Gongshang University, Hangzhou 310012, Zhejiang, China.
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2
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Buttar C, Alai H, Matanes FN, Cassidy MM, Stencel J, Le Jemtel TH. Full decongestion in acute heart failure therapy. Am J Med Sci 2024; 368:182-189. [PMID: 38880301 DOI: 10.1016/j.amjms.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 06/07/2024] [Accepted: 06/07/2024] [Indexed: 06/18/2024]
Abstract
Incomplete decongestion is the main cause of readmission in the early post-discharge period of a hospitalization for acute heart failure. Recent heart failure guidelines have highlighted initiation and rapid up-titration of quadruple therapy with angiotensin receptor neprilysin inhibitor, beta adrenergic receptor blocker, mineralocorticoid receptor antagonist, and sodium glucose cotransporter 2 inhibitor to prevent hospitalizations for heart failure with reduced ejection fraction. However, full decongestion remains the foremost therapeutic goal of hospitalization for heart failure. While early addition of sodium glucose cotransporter 2 inhibitors and mineralocorticoid receptor antagonists may be helpful, the value of the other therapeutics comes after decongestion is complete.
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Affiliation(s)
- Chandan Buttar
- Department of Cardiology, Tulane University Medical Center, 1415 Tulane Ave, New Orleans, LA 70112, USA; Southeast Louisiana Veterans Healthcare System, 2400 Canal Street, New Orleans, LA 70119, USA
| | - Hamid Alai
- Department of Cardiology, Tulane University Medical Center, 1415 Tulane Ave, New Orleans, LA 70112, USA; Southeast Louisiana Veterans Healthcare System, 2400 Canal Street, New Orleans, LA 70119, USA
| | - Faris N Matanes
- Department of Cardiology, Tulane University Medical Center, 1415 Tulane Ave, New Orleans, LA 70112, USA; Southeast Louisiana Veterans Healthcare System, 2400 Canal Street, New Orleans, LA 70119, USA
| | - Mark M Cassidy
- Department of Cardiology, Tulane University Medical Center, 1415 Tulane Ave, New Orleans, LA 70112, USA; Southeast Louisiana Veterans Healthcare System, 2400 Canal Street, New Orleans, LA 70119, USA
| | - Jason Stencel
- Department of Cardiology, Tulane University Medical Center, 1415 Tulane Ave, New Orleans, LA 70112, USA; Southeast Louisiana Veterans Healthcare System, 2400 Canal Street, New Orleans, LA 70119, USA
| | - Thierry H Le Jemtel
- Department of Cardiology, Tulane University Medical Center, 1415 Tulane Ave, New Orleans, LA 70112, USA; Southeast Louisiana Veterans Healthcare System, 2400 Canal Street, New Orleans, LA 70119, USA.
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3
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Misaka T, Sato Y, Sugawara Y, Ogawara R, Ichimura S, Tomita Y, Anzai F, Yokokawa T, Sato A, Shimizu T, Sato T, Oikawa M, Kobayashi A, Yoshihisa A, Takeishi Y. Elevated blood bicarbonate levels and long-term adverse outcomes in patients with chronic heart failure. ESC Heart Fail 2024. [PMID: 38970235 DOI: 10.1002/ehf2.14900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 04/13/2024] [Accepted: 05/24/2024] [Indexed: 07/08/2024] Open
Abstract
AIMS The bicarbonate (HCO3 -) buffer system is crucial for maintaining acid-base homeostasis and blood pH. Recent studies showed that elevated serum HCO3 - levels serve as an indicator of the beneficial effects of acetazolamide in improving decongestion in acute heart failure. In this study, we sought to clarify the clinical relevance and prognostic impact of HCO3 - in chronic heart failure (CHF). METHODS This cohort study enrolled 694 hospitalized patients with CHF (mean age 68.6 ± 14.6, 62% male) who underwent arterial blood sampling and exhibited neutral pH ranging from 7.35 to 7.45. We characterized the patients based on HCO3 - levels and followed them to register cardiac events. RESULTS Among the patients, 17.3% (120 patients) had HCO3 - levels exceeding 26 mmol/L. Patients presenting HCO3 - > 26 mmol/L were more likely to use loop diuretics and had higher serum sodium and lower potassium levels, but left ventricular ejection fraction did not differ compared with those with HCO3 - between 22 and 26 (379 patients) or those with HCO3 - < 22 mmol/L (195 patients). During a median follow-up period of 1950 days, Kaplan-Meier analysis revealed that patients with HCO3 - > 26 mmol/L had the lowest event-free survival rate from either cardiac deaths or heart failure-related rehospitalization (P < 0.01 and 0.03, respectively). In the multivariable Cox model, the presence of HCO3 - > 26 mmol/L independently predicted increased risks of each cardiac event with a hazard ratio of 2.31 and 1.69 (P < 0.01 and 0.02, respectively), while HCO3 - < 22 mmol/L was not associated with these events (hazard ratios, 0.99 and 1.19; P = 0.98 and 0.43, respectively). CONCLUSIONS Elevated blood HCO3 - levels may signify enhanced proximal nephron activation and loop diuretic resistance, leading to long-term adverse outcomes in patients with CHF, even within a normal pH range.
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Affiliation(s)
- Tomofumi Misaka
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
- Department of Community Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Yu Sato
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Yukiko Sugawara
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Ryo Ogawara
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Shohei Ichimura
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Yusuke Tomita
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Fumiya Anzai
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Tetsuro Yokokawa
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Akihiko Sato
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Takeshi Shimizu
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Takamasa Sato
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Masayoshi Oikawa
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Atsushi Kobayashi
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
- Department of Community Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
| | - Akiomi Yoshihisa
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
- Department of Clinical Laboratory Sciences, Fukushima Medical University School of Health Sciences, Fukushima, Japan
| | - Yasuchika Takeishi
- Department of Cardiovascular Medicine, Fukushima Medical University, Fukushima, Japan
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4
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Maheshwari V, Grobe N, Wang X, Patel A, Cherif A, Tao X, Chao J, Heide A, Nikolic D, Dong J, Kotanko P. Allo-Hemodialysis, a Novel Dialytic Treatment Option for Patients with Kidney Failure: Outcomes of Mathematical Modelling, Prototyping, and Ex Vivo Testing. Toxins (Basel) 2024; 16:292. [PMID: 39057932 PMCID: PMC11281302 DOI: 10.3390/toxins16070292] [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: 04/08/2024] [Revised: 05/24/2024] [Accepted: 06/06/2024] [Indexed: 07/28/2024] Open
Abstract
It has been estimated that in 2010, over two million patients with end-stage kidney disease may have faced premature death due to a lack of access to affordable renal replacement therapy, mostly dialysis. To address this shortfall in dialytic kidney replacement therapy, we propose a novel, cost-effective, and low-complexity hemodialysis method called allo-hemodialysis (alloHD). With alloHD, instead of conventional hemodialysis, the blood of a patient with kidney failure flows through the dialyzer's dialysate compartment counter-currently to the blood of a healthy subject (referred to as a "buddy") flowing through the blood compartment. Along the concentration and hydrostatic pressure gradients, uremic solutes and excess fluid are transferred from the patient to the buddy and subsequently excreted by the healthy kidneys of the buddy. We developed a mathematical model of alloHD to systematically explore dialysis adequacy in terms of weekly standard urea Kt/V. We showed that in the case of an anuric child (20 kg), four 4 h alloHD sessions are sufficient to attain a weekly standard Kt/V of >2.0. In the case of an anuric adult patient (70 kg), six 4 h alloHD sessions are necessary. As a next step, we designed and built an alloHD machine prototype that comprises off-the-shelf components. We then used this prototype to perform ex vivo experiments to investigate the transport of solutes, including urea, creatinine, and protein-bound uremic retention products, and to quantitate the accuracy and precision of the machine's ultrafiltration control. These experiments showed that alloHD performed as expected, encouraging future in vivo studies in animals with and without kidney failure.
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Affiliation(s)
- Vaibhav Maheshwari
- Renal Research Institute, 315 East 62nd Street, 3rd Floor, New York, NY 10065, USA; (V.M.); (N.G.); (X.W.); (A.P.); (A.C.); (X.T.); (J.C.)
| | - Nadja Grobe
- Renal Research Institute, 315 East 62nd Street, 3rd Floor, New York, NY 10065, USA; (V.M.); (N.G.); (X.W.); (A.P.); (A.C.); (X.T.); (J.C.)
| | - Xin Wang
- Renal Research Institute, 315 East 62nd Street, 3rd Floor, New York, NY 10065, USA; (V.M.); (N.G.); (X.W.); (A.P.); (A.C.); (X.T.); (J.C.)
| | - Amrish Patel
- Renal Research Institute, 315 East 62nd Street, 3rd Floor, New York, NY 10065, USA; (V.M.); (N.G.); (X.W.); (A.P.); (A.C.); (X.T.); (J.C.)
| | - Alhaji Cherif
- Renal Research Institute, 315 East 62nd Street, 3rd Floor, New York, NY 10065, USA; (V.M.); (N.G.); (X.W.); (A.P.); (A.C.); (X.T.); (J.C.)
| | - Xia Tao
- Renal Research Institute, 315 East 62nd Street, 3rd Floor, New York, NY 10065, USA; (V.M.); (N.G.); (X.W.); (A.P.); (A.C.); (X.T.); (J.C.)
| | - Joshua Chao
- Renal Research Institute, 315 East 62nd Street, 3rd Floor, New York, NY 10065, USA; (V.M.); (N.G.); (X.W.); (A.P.); (A.C.); (X.T.); (J.C.)
| | - Alexander Heide
- Fresenius Medical Care, 61352 Bad Homburg, Germany; (A.H.); (D.N.)
| | - Dejan Nikolic
- Fresenius Medical Care, 61352 Bad Homburg, Germany; (A.H.); (D.N.)
| | | | - Peter Kotanko
- Renal Research Institute, 315 East 62nd Street, 3rd Floor, New York, NY 10065, USA; (V.M.); (N.G.); (X.W.); (A.P.); (A.C.); (X.T.); (J.C.)
- Icahn School of Medicine at Mount Sinai, New York, NY 10128, USA
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5
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Gantsova E, Serova O, Vishnyakova P, Deyev I, Elchaninov A, Fatkhudinov T. Mechanisms and physiological relevance of acid-base exchange in functional units of the kidney. PeerJ 2024; 12:e17316. [PMID: 38699185 PMCID: PMC11064853 DOI: 10.7717/peerj.17316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 04/09/2024] [Indexed: 05/05/2024] Open
Abstract
This review discusses the importance of homeostasis with a particular emphasis on the acid-base (AB) balance, a crucial aspect of pH regulation in living systems. Two primary organ systems correct deviations from the standard pH balance: the respiratory system via gas exchange and the kidneys via proton/bicarbonate secretion and reabsorption. Focusing on kidney functions, we describe the complexity of renal architecture and its challenges for experimental research. We address specific roles of different nephron segments (the proximal convoluted tubule, the loop of Henle and the distal convoluted tubule) in pH homeostasis, while explaining the physiological significance of ion exchange processes maintained by the kidneys, particularly the role of bicarbonate ions (HCO3-) as an essential buffer system of the body. The review will be of interest to researchers in the fields of physiology, biochemistry and molecular biology, which builds a strong foundation and critically evaluates existing studies. Our review helps identify the gaps of knowledge by thoroughly understanding the existing literature related to kidney acid-base homeostasis.
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Affiliation(s)
- Elena Gantsova
- Avtsyn Research Institute of Human Morphology of Federal State Budgetary Scientific Institution “Petrovsky National Research Centre of Surgery”, Moscow, Russia
- Research Institute of Molecular and Cellular Medicine, Peoples’ Friendship University of Russia (RUDN University), Moscow, Russia
| | - Oxana Serova
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
| | - Polina Vishnyakova
- Research Institute of Molecular and Cellular Medicine, Peoples’ Friendship University of Russia (RUDN University), Moscow, Russia
- National Medical Research Center for Obstetrics, Gynecology and Perinatology Named after Academician V.I. Kulakov of Ministry of Healthcare of Russian Federation, Moscow, Russian Federation
| | - Igor Deyev
- Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
| | - Andrey Elchaninov
- Avtsyn Research Institute of Human Morphology of Federal State Budgetary Scientific Institution “Petrovsky National Research Centre of Surgery”, Moscow, Russia
- Research Institute of Molecular and Cellular Medicine, Peoples’ Friendship University of Russia (RUDN University), Moscow, Russia
| | - Timur Fatkhudinov
- Avtsyn Research Institute of Human Morphology of Federal State Budgetary Scientific Institution “Petrovsky National Research Centre of Surgery”, Moscow, Russia
- Research Institute of Molecular and Cellular Medicine, Peoples’ Friendship University of Russia (RUDN University), Moscow, Russia
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6
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Wiriyasermkul P, Moriyama S, Suzuki M, Kongpracha P, Nakamae N, Takeshita S, Tanaka Y, Matsuda A, Miyasaka M, Hamase K, Kimura T, Mita M, Sasabe J, Nagamori S. <sc>A</sc> multi-hierarchical approach reveals <sc>d</sc>-serine as a hidden substrate of sodium-coupled monocarboxylate transporters. eLife 2024; 12:RP92615. [PMID: 38650461 PMCID: PMC11037918 DOI: 10.7554/elife.92615] [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] [Indexed: 04/25/2024] Open
Abstract
Transporter research primarily relies on the canonical substrates of well-established transporters. This approach has limitations when studying transporters for the low-abundant micromolecules, such as micronutrients, and may not reveal physiological functions of the transporters. While d-serine, a trace enantiomer of serine in the circulation, was discovered as an emerging biomarker of kidney function, its transport mechanisms in the periphery remain unknown. Here, using a multi-hierarchical approach from body fluids to molecules, combining multi-omics, cell-free synthetic biochemistry, and ex vivo transport analyses, we have identified two types of renal d-serine transport systems. We revealed that the small amino acid transporter ASCT2 serves as a d-serine transporter previously uncharacterized in the kidney and discovered d-serine as a non-canonical substrate of the sodium-coupled monocarboxylate transporters (SMCTs). These two systems are physiologically complementary, but ASCT2 dominates the role in the pathological condition. Our findings not only shed light on renal d-serine transport, but also clarify the importance of non-canonical substrate transport. This study provides a framework for investigating multiple transport systems of various trace micromolecules under physiological conditions and in multifactorial diseases.
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Affiliation(s)
- Pattama Wiriyasermkul
- Center for SI Medical Research, The Jikei University School of MedicineTokyoJapan
- Department of Laboratory Medicine, The Jikei University School of MedicineTokyoJapan
- Department of Collaborative Research for Biomolecular Dynamics, Nara Medical UniversityNaraJapan
| | - Satomi Moriyama
- Department of Collaborative Research for Biomolecular Dynamics, Nara Medical UniversityNaraJapan
| | - Masataka Suzuki
- Department of Pharmacology, Keio University School of MedicineTokyoJapan
| | - Pornparn Kongpracha
- Center for SI Medical Research, The Jikei University School of MedicineTokyoJapan
- Department of Laboratory Medicine, The Jikei University School of MedicineTokyoJapan
| | - Nodoka Nakamae
- Department of Collaborative Research for Biomolecular Dynamics, Nara Medical UniversityNaraJapan
| | - Saki Takeshita
- Department of Collaborative Research for Biomolecular Dynamics, Nara Medical UniversityNaraJapan
| | - Yoko Tanaka
- Department of Collaborative Research for Biomolecular Dynamics, Nara Medical UniversityNaraJapan
| | - Akina Matsuda
- Department of Pharmacology, Keio University School of MedicineTokyoJapan
| | - Masaki Miyasaka
- Center for SI Medical Research, The Jikei University School of MedicineTokyoJapan
- Department of Laboratory Medicine, The Jikei University School of MedicineTokyoJapan
| | - Kenji Hamase
- Graduate School of Pharmaceutical Sciences, Kyushu UniversityFukuokaJapan
| | - Tomonori Kimura
- KAGAMI Project, National Institutes of Biomedical Innovation, Health and NutritionOsakaJapan
- Reverse Translational Research Project, Center for Rare Disease Research, National Institutes of Biomedical Innovation, Health and NutritionOsakaJapan
| | | | - Jumpei Sasabe
- Department of Pharmacology, Keio University School of MedicineTokyoJapan
| | - Shushi Nagamori
- Center for SI Medical Research, The Jikei University School of MedicineTokyoJapan
- Department of Laboratory Medicine, The Jikei University School of MedicineTokyoJapan
- Department of Collaborative Research for Biomolecular Dynamics, Nara Medical UniversityNaraJapan
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7
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Lee BR. Renal Tubular Acidosis in the Neonate. Neoreviews 2024; 25:e99-e106. [PMID: 38296789 DOI: 10.1542/neo.25-2-e99] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
See Bonus NeoBriefs videos and downloadable teaching slides Metabolic acidosis can manifest in the neonatal period and cause significant morbidity and mortality in neonates. Preterm infants are at an even higher risk of developing metabolic acidosis. If the acidosis results from a dysfunction of acid-base homeostasis by the renal system, the disorder is known as renal tubular acidosis (RTA). In this review, we will describe renal development and normal acid-base homeostasis by the renal system. We will also discuss the pathophysiology of the different types of RTA, laboratory findings to aid in diagnosis, and treatment considerations. Understanding RTA will help neonatal clinicians recognize and diagnose an infant affected by RTA and initiate treatment in a timely manner.
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Affiliation(s)
- Brian R Lee
- Department of Neonatology, Southern California Permanente Medical Group, Pasadena, CA
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8
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Tabibzadeh N, Satlin LM, Jain S, Morizane R. Navigating the kidney organoid: insights into assessment and enhancement of nephron function. Am J Physiol Renal Physiol 2023; 325:F695-F706. [PMID: 37767571 PMCID: PMC10878724 DOI: 10.1152/ajprenal.00166.2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 09/18/2023] [Accepted: 09/20/2023] [Indexed: 09/29/2023] Open
Abstract
Kidney organoids are three-dimensional structures generated from pluripotent stem cells (PSCs) that are capable of recapitulating the major structures of mammalian kidneys. As this technology is expected to be a promising tool for studying renal biology, drug discovery, and regenerative medicine, the functional capacity of kidney organoids has emerged as a critical question in the field. Kidney organoids produced using several protocols harbor key structures of native kidneys. Here, we review the current state, recent advances, and future challenges in the functional characterization of kidney organoids, strategies to accelerate and enhance kidney organoid functions, and access to PSC resources to advance organoid research. The strategies to construct physiologically relevant kidney organoids include the use of organ-on-a-chip technologies that integrate fluid circulation and improve organoid maturation. These approaches result in increased expression of the major tubular transporters and elements of mechanosensory signaling pathways suggestive of improved functionality. Nevertheless, continuous efforts remain crucial to create kidney tissue that more faithfully replicates physiological conditions for future applications in kidney regeneration medicine and their ethical use in patient care.NEW & NOTEWORTHY Kidney organoids are three-dimensional structures derived from stem cells, mimicking the major components of mammalian kidneys. Although they show great promise, their functional capacity has become a critical question. This review explores the advancements and challenges in evaluating and enhancing kidney organoid function, including the use of organ-on-chip technologies, multiomics data, and in vivo transplantation. Integrating these approaches to further enhance their physiological relevance will continue to advance disease modeling and regenerative medicine applications.
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Affiliation(s)
- Nahid Tabibzadeh
- Nephrology Division, Massachusetts General Hospital, Boston, Massachusetts, United States
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States
| | - Lisa M Satlin
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York, United States
| | - Sanjay Jain
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States
- Department of Pathology, Washington University School of Medicine, St. Louis, Missouri, United States
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, United States
| | - Ryuji Morizane
- Nephrology Division, Massachusetts General Hospital, Boston, Massachusetts, United States
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States
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9
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Albuquerque ALB, Dos Santos Borges R, Conegundes AF, Dos Santos EE, Fu FMM, Araujo CT, Vaz de Castro PAS, Simões E Silva AC. Inherited Fanconi syndrome. World J Pediatr 2023; 19:619-634. [PMID: 36729281 DOI: 10.1007/s12519-023-00685-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 01/08/2023] [Indexed: 02/03/2023]
Abstract
BACKGROUND Fanconi-Debré-de Toni syndrome (also known as Fanconi renotubular syndrome, or FRST) profoundly increased the understanding of the functions of the proximal convoluted tubule (PCT) and provided important insights into the pathophysiology of several kidney diseases and drug toxicities. DATA SOURCES We searched Pubmed and Scopus databases to find relevant articles about FRST. This review article focuses on the physiology of the PCT, as well as on the physiopathology of FRST in children, its diagnosis, and treatment. RESULTS FRST encompasses a wide variety of inherited and acquired PCT alterations that lead to impairment of PCT reabsorption. In children, FRST often presents as a secondary feature of systemic disorders that impair energy supply, such as Lowe's syndrome, Dent's disease, cystinosis, hereditary fructose intolerance, galactosemia, tyrosinemia, Alport syndrome, and Wilson's disease. Although rare, congenital causes of FRST greatly impact the morbidity and mortality of patients and impose diagnostic challenges. Furthermore, its treatment is diverse and considers the ability of the clinician to identify the correct etiology of the disease. CONCLUSION The early diagnosis and treatment of pediatric patients with FRST improve the prognosis and the quality of life.
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Affiliation(s)
- Anna Luiza Braga Albuquerque
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Rafael Dos Santos Borges
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Ana Flávia Conegundes
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Erika Emmylaine Dos Santos
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Frederico Moreira Man Fu
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Clara Tavares Araujo
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Pedro Alves Soares Vaz de Castro
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Ana Cristina Simões E Silva
- Interdisciplinary Laboratory of Medical Investigation, Unit of Pediatric Nephrology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil.
- Department of Pediatrics, Faculty of Medicine, UFMG, Alfredo Balena Avenue, 190, 2Nd Floor, Room # 281, Belo Horizonte, MG, 30130-100, Brazil.
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10
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Lee D, Hong JH. Multiple-Factors-Induced Rheumatoid Arthritis Synoviocyte Activation Is Attenuated by the α2-Adrenergic Receptor Agonist Dexmedetomidine. Int J Mol Sci 2023; 24:10756. [PMID: 37445932 DOI: 10.3390/ijms241310756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/15/2023] Open
Abstract
Dexmedetomidine (Dex) has analgesic and sedative properties and anti-inflammatory functions. Although the effects of Dex on arthritis have been revealed, the physiological mechanism underlying the interaction between Dex and rheumatoid arthritis (RA)-mediated inflammatory cytokines has not been fully studied. Inflamed and migrated fibroblast-like synoviocytes (FLSs) are involved in RA severity. Thus, we aimed to determine the effects of Dex on RA-FLSs treated with inflammatory cytokines and a growth factor as multiple stimulating inputs. TNF-α, IL-6, and EGF as multiple stimulating inputs increased the cAMP concentration of RA-FLSs, while Dex treatment reduced cAMP concentration. Dex reduced electroneutral sodium-bicarbonate cotransporter 1 (NBCn1) expression, NBC activity, and subsequent RA-FLS migration. The mRNA expression levels of RA-related factors, such as inflammatory cytokines and osteoclastogenesis factors, were enhanced by multiple-input treatment. Notably, Dex effectively reduced these expression levels in RA-FLSs. These results indicate that multiple inflammatory or stimulating inputs enhance RA-FLS migration, and treatment with Dex relieves activated RA-FLSs, suggesting that Dex is a potential therapeutic drug for RA.
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Affiliation(s)
- Dongun Lee
- Department of Health Sciences and Technology, Lee Gil Ya Cancer and Diabetes Institute, GAIHST, Gachon University, 155 Getbeolro, Yeonsu-gu, Incheon 21999, Republic of Korea
| | - Jeong Hee Hong
- Department of Health Sciences and Technology, Lee Gil Ya Cancer and Diabetes Institute, GAIHST, Gachon University, 155 Getbeolro, Yeonsu-gu, Incheon 21999, Republic of Korea
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11
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Martens P, Verbrugge FH, Dauw J, Nijst P, Meekers E, Augusto SN, Ter Maaten JM, Heylen L, Damman K, Mebazaa A, Filippatos G, Ruschitzka F, Tang WHW, Dupont M, Mullens W. Pre-treatment bicarbonate levels and decongestion by acetazolamide: the ADVOR trial. Eur Heart J 2023; 44:1995-2005. [PMID: 37138385 DOI: 10.1093/eurheartj/ehad236] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/26/2023] [Accepted: 04/04/2023] [Indexed: 05/05/2023] Open
Abstract
AIMS Acetazolamide inhibits proximal tubular sodium and bicarbonate re-absorption and improved decongestive response in acute heart failure in the ADVOR trial. It is unknown whether bicarbonate levels alter the decongestive response to acetazolamide. METHODS AND RESULTS This is a sub-analysis of the randomized, double-blind, placebo-controlled ADVOR trial that randomized 519 patients with acute heart failure and volume overload in a 1:1 ratio to intravenous acetazolamide (500 mg/day) or matching placebo on top of standardized intravenous loop diuretics (dose equivalent of twice oral maintenance dose). The primary endpoint was complete decongestion after 3 days of treatment (morning of day 4). Impact of baseline HCO3 levels on the treatment effect of acetazolamide was assessed. : Of the 519 enrolled patients, 516 (99.4%) had a baseline HCO3 measurement. Continuous HCO3 modelling illustrated a higher proportional treatment effect for acetazolamide if baseline HCO3 ≥ 27 mmol/l. A total of 234 (45%) had a baseline HCO3 ≥ 27 mmol/l. Randomization towards acetazolamide improved decongestive response over the entire range of baseline HCO3- levels (P = 0.004); however, patients with elevated baseline HCO3 exhibited a significant higher response to acetazolamide [primary endpoint: no vs. elevated HCO3; OR 1.37 (0.79-2.37) vs. OR 2.39 (1.35-4.22), P-interaction = 0.065), with higher proportional diuretic and natriuretic response (both P-interaction < 0.001), greater reduction in congestion score on consecutive days (treatment × time by HCO3-interaction <0.001) and length of stay (P-interaction = 0.019). The larger proportional treatment effect was mainly explained by the development of diminished decongestive response in the placebo arm (loop diuretics only), both with regard to reaching the primary endpoint of decongestion as well as reduction in congestion score. Development of elevated HCO3 further worsened decongestive response in the placebo arm (P-interaction = 0.041). A loop diuretic only strategy was associated with an increase in the HCO3 during the treatment phase which was prevented by acetazolamide (day 3: placebo 74.8% vs. acetazolamide 41.3%, P < 0.001). CONCLUSION Acetazolamide improves decongestive response over the entire range of HCO3- levels; however, the treatment response is magnified in patients with baseline or loop diuretic-induced elevated HCO3 (marker of proximal nephron NaHCO3 retention) by specifically counteracting this component of diuretic resistance.
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Affiliation(s)
- Pieter Martens
- Department of Cardiovascular Medicine, Heart, Vascular and Thoracic Institute, Cleveland Clinic, Cleveland, OH, USA
- Department of Cardiology, Ziekenhuis Oost-Limburg A.V., Schiepse bos 6, 3600 Genk, Belgium
| | - Frederik H Verbrugge
- Centre for Cardiovascular Diseases, University Hospital Brussels, Jette, Belgium
- Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Jette, Belgium
| | - Jeroen Dauw
- Department of Cardiology, Ziekenhuis Oost-Limburg A.V., Schiepse bos 6, 3600 Genk, Belgium
- Faculty of Medicine and Life Science, Hasselt University, Martelarenlaan 42, 3500 Hasselt, Belgium
| | - Petra Nijst
- Department of Cardiology, Ziekenhuis Oost-Limburg A.V., Schiepse bos 6, 3600 Genk, Belgium
| | - Evelyne Meekers
- Department of Cardiology, Ziekenhuis Oost-Limburg A.V., Schiepse bos 6, 3600 Genk, Belgium
- Centre for Cardiovascular Diseases, University Hospital Brussels, Jette, Belgium
| | - Silvio Nunes Augusto
- Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Jozine M Ter Maaten
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Line Heylen
- Department of Nefrology, Ziekenhuis Oost-Limburg A.V., Genk, Belgium
| | - Kevin Damman
- Department of Cardiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Alexandre Mebazaa
- Department of Medicine, Université Paris Cité, Inserm MASCOT, APHP, Paris, France
| | - Gerasimos Filippatos
- Department of Cardiology, National and Kapodistrian University of Athens, Athens University Hospital Attikon, Athens, Greece
| | - Frank Ruschitzka
- Department of Cardiology, University Heart Center, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Wai Hong Wilson Tang
- Department of Cardiovascular Medicine, Heart, Vascular and Thoracic Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Matthias Dupont
- Department of Cardiology, Ziekenhuis Oost-Limburg A.V., Schiepse bos 6, 3600 Genk, Belgium
| | - Wilfried Mullens
- Department of Cardiology, Ziekenhuis Oost-Limburg A.V., Schiepse bos 6, 3600 Genk, Belgium
- Faculty of Medicine and Life Science, Hasselt University, Martelarenlaan 42, 3500 Hasselt, Belgium
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12
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Li X, Zhuo J. Intracellular Angiotensin II Stimulation of Sodium Transporter Expression in Proximal Tubule Cells via AT 1 (AT 1a) Receptor-Mediated, MAP Kinases ERK1/2- and NF-кB-Dependent Signaling Pathways. Cells 2023; 12:1492. [PMID: 37296613 PMCID: PMC10252550 DOI: 10.3390/cells12111492] [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: 03/17/2023] [Revised: 05/23/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
The current prevailing paradigm in the renin-angiotensin system dictates that most, if not all, biological, physiological, and pathological responses to its most potent peptide, angiotensin II (Ang II), are mediated by extracellular Ang II activating its cell surface receptors. Whether intracellular (or intracrine) Ang II and its receptors are involved remains incompletely understood. The present study tested the hypothesis that extracellular Ang II is taken up by the proximal tubules of the kidney by an AT1 (AT1a) receptor-dependent mechanism and that overexpression of an intracellular Ang II fusion protein (ECFP/Ang II) in mouse proximal tubule cells (mPTC) stimulates the expression of Na+/H+ exchanger 3 (NHE3), Na+/HCO3- cotransporter, and sodium and glucose cotransporter 2 (Sglt2) by AT1a/MAPK/ERK1/2/NF-kB signaling pathways. mPCT cells derived from male wild-type and type 1a Ang II receptor-deficient mice (Agtr1a-/-) were transfected with an intracellular enhanced cyan fluorescent protein-tagged Ang II fusion protein, ECFP/Ang II, and treated without or with AT1 receptor blocker losartan, AT2 receptor blocker PD123319, MEK1/MEK2 inhibitor U0126, NF-кB inhibitor RO 106-9920, or p38 MAP kinase inhibitor SB202196, respectively. In wild-type mPCT cells, the expression of ECFP/Ang II significantly increased NHE3, Na+/HCO3-, and Sglt2 expression (p < 0.01). These responses were accompanied by >3-fold increases in the expression of phospho-ERK1/2 and the p65 subunit of NF-кB (p < 0.01). Losartan, U0126, or RO 106-9920 all significantly attenuated ECFP/Ang II-induced NHE3 and Na+/HCO3- expression (p < 0.01). Deletion of AT1 (AT1a) receptors in mPCT cells attenuated ECFP/Ang II-induced NHE3 and Na+/HCO3- expression (p < 0.01). Interestingly, the AT2 receptor blocker PD123319 also attenuated ECFP/Ang II-induced NHE3 and Na+/HCO3- expression (p < 0.01). These results suggest that, similar to extracellular Ang II, intracellular Ang II may also play an important role in Ang II receptor-mediated proximal tubule NHE3, Na+/HCO3-, and Sglt2 expression by activation of AT1a/MAPK/ERK1/2/NF-kB signaling pathways.
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Affiliation(s)
- Xiaochun Li
- Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, LA 70112-2699, USA;
- Department of Physiology, Tulane University School of Medicine, New Orleans, LA 70112-2699, USA
| | - Jialong Zhuo
- Tulane Hypertension and Renal Center of Excellence, Tulane University School of Medicine, New Orleans, LA 70112-2699, USA;
- Department of Physiology, Tulane University School of Medicine, New Orleans, LA 70112-2699, USA
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13
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Shin S, Boadi EA, Bandyopadhyay BC. Ablation of TRPC3 compromises bicarbonate and phosphate transporter activity in mice proximal tubular cells. Clin Exp Pharmacol Physiol 2023; 50:247-255. [PMID: 36433745 PMCID: PMC10258833 DOI: 10.1111/1440-1681.13741] [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: 05/11/2022] [Revised: 11/19/2022] [Accepted: 11/21/2022] [Indexed: 11/28/2022]
Abstract
Proximal tubular (PT) cells reabsorb most calcium (Ca2+ ), phosphate (PO4 3- ), bicarbonate (HCO3 - ), and oxalate (C2 O4 2- ) ions. We have shown that mice lacking Transient Receptor Potential Canonical 3 (TRPC3-/- ) channel are moderately hypercalciuric with presentation of luminal calcium phosphate (CaP) crystals at the loop of Henle (LOH). However, other predisposing factors for such crystal deposition are unknown. Thus, we examined the distinctions in functional status of HCO3 - , PO4 3- , and C2 O4 2- transporters in PT cells of wild type (WT) and TRPC3-/- mice by whole-cell patch clamp techniques to assess their contribution in the development of LOH CaP crystals. Here we show the development of concentration dependent HCO3 - -induced currents in all PT cells, which was confirmed by using specific HCO3 - channel inhibitor, S0859. Interestingly, such activities were diminished in PT cells from TRPC3-/- mice, suggesting reduced HCO3 - transport in absence of TRPC3. While PO4 3- -induced currents were also concentration dependent in all PT cells (confirmed by PO4 3- channel inhibitor, PF-06869206), those activities were reduced in absence of TRPC3, suggesting lower PO4 3- reabsorption that can leave excess luminal PO4 3- . Next, we applied thiosulfate (O3 S2 2 - ) as a competitive inhibitor of the SLC26a6 transporter upon C2 O4 2- current activation and observed a reduced C2 O4 2- -induced conductance which was greater in TRPC3-/- PT cells. Together, these results suggest that the reduced activities of HCO3 - , PO4 3- , and C2 O4 2- transporters in moderately hypercalciuric (TRPC3-/- ) PT cells can create a predisposing condition for CaP and CaP tubular crystallization, enabling CaP crystal formation in LOH of TRPC3-/- mice.
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Affiliation(s)
- Samuel Shin
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, Washington, Columbia, USA
| | - Eugenia Awuah Boadi
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, Washington, Columbia, USA
| | - Bidhan C. Bandyopadhyay
- Calcium Signaling Laboratory, Research Service, Veterans Affairs Medical Center, Washington, Columbia, USA
- Division of Renal Diseases & Hypertension, Department of Medicine, The George Washington University, Washington, Columbia, USA
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14
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Tabibzadeh N, Crambert G. Mechanistic insights into the primary and secondary alterations of renal ion and water transport in the distal nephron. J Intern Med 2023; 293:4-22. [PMID: 35909256 PMCID: PMC10087581 DOI: 10.1111/joim.13552] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The kidneys, by equilibrating the outputs to the inputs, are essential for maintaining the constant volume, pH, and electrolyte composition of the internal milieu. Inability to do so, either because of internal kidney dysfunction (primary alteration) or because of some external factors (secondary alteration), leads to pathologies of varying severity, leading to modification of these parameters and affecting the functions of other organs. Alterations of the functions of the collecting duct (CD), the most distal part of the nephron, have been extensively studied and have led to a better diagnosis, better management of the related diseases, and the development of therapeutic tools. Thus, dysfunctions of principal cell-specific transporters such as ENaC or AQP2 or its receptors (mineralocorticoid or vasopressin receptors) caused by mutations or by compounds present in the environment (lithium, antibiotics, etc.) have been demonstrated in a variety of syndromes (Liddle, pseudohypoaldosteronism type-1, diabetes insipidus, etc.) affecting salt, potassium, and water balance. In parallel, studies on specific transporters (H+ -ATPase, anion exchanger 1) in intercalated cells have revealed the mechanisms of related tubulopathies like distal renal distal tubular acidosis or Sjögren syndrome. In this review, we will recapitulate the mechanisms of most of the primary and secondary alteration of the ion transport system of the CD to provide a better understanding of these diseases and highlight how a targeted perturbation may affect many different pathways due to the strong crosstalk and entanglements between the different actors (transporters, cell types).
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Affiliation(s)
- Nahid Tabibzadeh
- Laboratoire de Physiologie Rénale et TubulopathiesCentre de Recherche des CordeliersINSERMSorbonne UniversitéUniversité Paris CitéParisFrance
- EMR 8228 Unité Métabolisme et Physiologie RénaleCNRSParisFrance
- Assistance Publique Hôpitaux de ParisHôpital BichâtParisFrance
| | - Gilles Crambert
- Laboratoire de Physiologie Rénale et TubulopathiesCentre de Recherche des CordeliersINSERMSorbonne UniversitéUniversité Paris CitéParisFrance
- EMR 8228 Unité Métabolisme et Physiologie RénaleCNRSParisFrance
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15
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Abstract
The kidney maintains electrolyte, water, and acid-base balance, eliminates foreign and waste compounds, regulates blood pressure, and secretes hormones. There are at least 16 different highly specialized epithelial cell types in the mammalian kidney. The number of specialized endothelial cells, immune cells, and interstitial cell types might even be larger. The concerted interplay between different cell types is critical for kidney function. Traditionally, cells were defined by their function or microscopical morphological appearance. With the advent of new single-cell modalities such as transcriptomics, epigenetics, metabolomics, and proteomics we are entering into a new era of cell type definition. This new technological revolution provides new opportunities to classify cells in the kidney and understand their functions.
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Affiliation(s)
- Michael S Balzer
- Department of Medicine, Renal Electrolyte and Hypertension Division, University of Pennsylvania, Philadelphia, Pennsylvania, USA;
- Institute of Diabetes Obesity and Metabolism, University of Pennsylvania, Philadelphia, Philadelphia, USA
| | - Tibor Rohacs
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Katalin Susztak
- Department of Medicine, Renal Electrolyte and Hypertension Division, University of Pennsylvania, Philadelphia, Pennsylvania, USA;
- Institute of Diabetes Obesity and Metabolism, University of Pennsylvania, Philadelphia, Philadelphia, USA
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16
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Jasso-Avila MI, Castro-Argüelles AA, Centeno-Del Toro SM, Rivera-López E, Valadez-Castillo FJ. Base excess measured at hospital admission is useful for predicting diabetic ketoacidosis severity and resolution time in adult patients. Diabetes Metab Syndr 2022; 16:102385. [PMID: 35026666 DOI: 10.1016/j.dsx.2021.102385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 12/28/2021] [Accepted: 12/29/2021] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND AIMS This study aimed to identify the biochemical factors measured at hospital admission that could predict diabetes ketoacidosis (DKA) resolution time in adult patients. MATERIALS AND METHODS This retrospective study included 79 patients >18 years of age. Multivariate analyses were performed to determine which variables might predict DKA resolution time. Biochemical parameters between the two DKA resolution time groups were compared. RESULTS Using multiple linear regression models, acidosis time was found to decrease by 29 h if the pH value increased by one unit, 0.64 h if the base excess (BE) value increased by 1 mmol, and 1.09 h if the bicarbonate (HCO3-) value increased by 1 mmol. The biochemical parameters that differed between the two groups were pH, HCO3-, and BE. Patients with delayed resolution of DKA had a blood pH of 7.1 (±0.18), HCO3- of 5.1 mmol (2.9-11.6 mmol), and BE of -21.5 mmol (-28.2 to -14.4 mmol) at hospital admission. CONCLUSIONS Lower pH, HCO3-, and BE values at hospital admission may predict longer DKA resolution times in adult patients. In addition, BE may predict DKA severity.
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Affiliation(s)
- María Isabel Jasso-Avila
- Residente de Endocrinología. Instituto Nacional de Ciencias Médicas y Nutrición "Salvador Zubiran", Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | | | | | - Emmanuel Rivera-López
- Departamento de Endocrinología, Hospital Central "Ignacio Morones Prieto", San Luis Potosí, Mexico
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17
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Yamazaki O, Yamashita M, Li J, Ochiai-Homma F, Yoshida T, Hirahashi J, Furukawa T, Kozuma K, Fujigaki Y, Seki G, Hayashi M, Shibata S. A novel I551F variant of the Na +/HCO 3- cotransporter NBCe1-A shows reduced cell surface expression, resulting in diminished transport activity. Am J Physiol Renal Physiol 2021; 321:F771-F784. [PMID: 34719949 DOI: 10.1152/ajprenal.00584.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Homozygous mutations in SLC4A4, which encodes the electrogenic Na+/[Formula: see text] cotransporter (NBCe1), cause proximal renal tubular acidosis associated with extrarenal symptoms. Although 17` mutated sites in SLC4A4 have thus far been identified among patients with proximal renal tubular acidosis, the physiological significance of other nonsynonymous single-nucleotide variants (SNVs) remains largely undetermined. Here, we investigated the functional properties of SNVs in NBCe1. From the National Center for Biotechnology Information dbSNP database, we identified 13 SNVs that have not previously been characterized in the highly conserved, transmembrane domains of NBCe1-A. Immunocytochemical analysis revealed that the I551F variant was present predominantly in the cytoplasm in human embryonic kidney (HEK)-293 cells, whereas all other SNVs did not show as dramatic a change in subcellular distribution. Western blot analysis in HEK-293 cells demonstrated that the I551F variant showed impaired glycosylation and a 69% reduction in cell surface levels. To determine the role of I551 in more detail, we examined the significance of various artificial mutants in both nonpolarized HEK-293 cells and polarized Madin-Darby canine kidney cells, which indicated that only I551F substitution resulted in cytoplasmic retention. Moreover, functional analysis using Xenopus oocytes demonstrated that the I551F variant had a significantly reduced activity corresponding to 39% of that of the wild-type, whereas any other SNVs and artificial I551 mutants did not show significant changes in activity. Finally, immunofluorescence experiments in HEK-293 cells indicated that the I551F variant retained wild-type NBCe1-A in the cytoplasm. These data demonstrate that the I551F variant of NBCe1-A shows impaired transport activity predominantly through cytoplasmic retention and suggest that the variant can have a dominant negative effect by forming complexes with wild-type NBCe1-A.NEW & NOTEWORTHY Electrogenic Na+/[Formula: see text] cotransporter 1-A (NBCe1-A) in the proximal tubule regulates the acid/base balance and fluid volume homeostasis. From the National Center for Biotechnology Information dbSNP database, we identified the I551F variant of NBCe1-A, which showed reduced glycosylation, cell surface expression, and transport activity. We also found that the I551F variant can exert a dominant negative effect on wild-type NBCe1-A, suggesting its physiological significance.
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Affiliation(s)
- Osamu Yamazaki
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan.,Department of General Medicine, Keio University School of Medicine, Tokyo, Japan.,Apheresis and Dialysis Center, Keio University School of Medicine, Tokyo, Japan
| | - Maho Yamashita
- Apheresis and Dialysis Center, Keio University School of Medicine, Tokyo, Japan
| | - Jinping Li
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Fumika Ochiai-Homma
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Tadashi Yoshida
- Department of General Medicine, Keio University School of Medicine, Tokyo, Japan.,Apheresis and Dialysis Center, Keio University School of Medicine, Tokyo, Japan
| | - Junichi Hirahashi
- Department of General Medicine, Keio University School of Medicine, Tokyo, Japan.,Apheresis and Dialysis Center, Keio University School of Medicine, Tokyo, Japan
| | - Taiji Furukawa
- Department of Laboratory Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Ken Kozuma
- Division of Cardiology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Yoshihide Fujigaki
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | | | - Matsuhiko Hayashi
- Department of General Medicine, Keio University School of Medicine, Tokyo, Japan.,Apheresis and Dialysis Center, Keio University School of Medicine, Tokyo, Japan.,Kawakita General Hospital, Center for Clinical Education, Tokyo, Japan
| | - Shigeru Shibata
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
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18
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Renick PJ, Mulgaonkar A, Co CM, Wu CY, Zhou N, Velazquez A, Pennington J, Sherwood A, Dong H, Castellino L, Öz OK, Tang L, Sun X. Imaging of Actively Proliferating Bacterial Infections by Targeting the Bacterial Metabolic Footprint with d-[5- 11C]-Glutamine. ACS Infect Dis 2021; 7:347-361. [PMID: 33476123 DOI: 10.1021/acsinfecdis.0c00617] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Since most d-amino acids (DAAs) are utilized by bacterial cells but not by mammalian eukaryotic hosts, recently DAA-based molecular imaging strategies have been extensively explored for noninvasively differentiating bacterial infections from the host's inflammatory responses. Given glutamine's pivotal role in bacterial survival, cell growth, biofilm formation, and even virulence, here we report a new positron emission tomography (PET) imaging approach using d-5-[11C]glutamine (d-[5-11C]-Gln) for potential clinical assessment of bacterial infection through a comparative study with its l-isomer counterpart, l-[5-11C]-Gln. In both control and infected mice, l-[5-11C]-Gln had substantially higher uptake levels than d-[5-11C]-Gln in most organs except the kidneys, showing the expected higher use of l-[5-11C]-Gln by mammalian tissues and more efficient renal excretion of d-[5-11C]-Gln. Importantly, our work demonstrates that PET imaging with d-[5-11C]-Gln is capable of detecting infections induced by both Escherichia coli (E. coli) and methicillin-resistant Staphylococcus aureus (MRSA) in a dual-infection murine myositis model with significantly higher infection-to-background contrast than with l-[5-11C]-Gln (in E. coli, 1.64; in MRSA, 2.62, p = 0.0004). This can be attributed to the fact that d-[5-11C]-Gln is utilized by bacteria while being more efficiently cleared from the host tissues. We confirmed the bacterial infection imaging specificity of d-[5-11C]-Gln by comparing its uptake in active bacterial infections versus sterile inflammation and with 2-deoxy-2-[18F]fluoroglucose ([18F]FDG). These results together demonstrate the translational potential of PET imaging with d-[5-11C]-Gln for the noninvasive detection of bacterial infectious diseases in humans.
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19
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Marable SS, Chung E, Park JS. Hnf4a Is Required for the Development of Cdh6-Expressing Progenitors into Proximal Tubules in the Mouse Kidney. J Am Soc Nephrol 2020; 31:2543-2558. [PMID: 32764140 DOI: 10.1681/asn.2020020184] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 07/06/2020] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Hepatocyte NF 4α (Hnf4a) is a major regulator of renal proximal tubule (PT) development. In humans, a mutation in HNF4A impairs PT functions and is associated with Fanconi renotubular syndrome (FRTS). In mice, mosaic deletion of Hnf4a in the developing kidney reduces the population of PT cells, leading to FRTS-like symptoms. The molecular mechanisms underlying the role of Hnf4a in PT development remain unclear. METHODS The gene deletion tool Osr2Cre removed Hnf4a in developing nephrons in mice, generating a novel model for FRTS. Immunofluorescence analysis characterized the mutant phenotype, and lineage analysis tested whether Cadherin-6 (Cdh6)-expressing cells are PT progenitors. Genome-wide mapping of Hnf4a binding sites and differential gene analysis of Hnf4a mutant kidneys identified direct target genes of Hnf4a. RESULTS Deletion of Hnf4a with Osr2Cre led to the complete loss of mature PT cells, lethal to the Hnf4a mutant mice. Cdh6high, lotus tetragonolobus lectin-low (LTLlow) cells serve as PT progenitors and demonstrate higher proliferation than Cdh6low, LTLhigh differentiated PT cells. Additionally, Hnf4a is required for PT progenitors to differentiate into mature PT cells. Genomic analyses revealed that Hnf4a directly regulates the expression of genes involved in transmembrane transport and metabolism. CONCLUSIONS Hnf4a promotes the differentiation of PT progenitors into mature PT cells by regulating the expression of genes associated with reabsorption, the major function of PT cells.
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Affiliation(s)
- Sierra S Marable
- Division of Pediatric Urology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Eunah Chung
- Division of Pediatric Urology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Joo-Seop Park
- Division of Pediatric Urology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio .,Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Department of Surgery, University of Cincinnati College of Medicine, Cincinnati, Ohio
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The pHLIP system as a vehicle for microRNAs in the kidney. Nefrologia 2020; 40:491-498. [PMID: 32693933 DOI: 10.1016/j.nefro.2020.05.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/11/2020] [Accepted: 05/20/2020] [Indexed: 11/23/2022] Open
Abstract
MicroRNAs (miRNAs) are small endogenous RNAs that regulate gene expression through post-transcriptional repression of their target messenger RNAs. A study of changes in expression of certain miRNAs in the kidney has supplied evidence on their pathogenic role and therapeutic potential in nephrology. This review proposes a nanotechnology approach based on the binding of analogs or inhibitors of miRNAs formed by peptide nucleic acids (PNAs) to peptides with a transmembrane structure sensitive to a low pH, called pHLIPs (pH [low] insertion peptides). The review draws on the concept that an acidic pH in the microenvironment of the renal tubule may facilitate concentration and distribution of the pHLIP-PNA complex in this organ. In this context, we have demonstrated for the first time that targeted administration of miR-33 inhibitors with the pHLIP system effectively prevents the development of renal fibrosis, thus opening up this technology to new strategies for diagnosis and treatment of kidney diseases.
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Transcriptomic Analysis of Gill and Kidney from Asian Seabass ( Lates calcarifer) Acclimated to Different Salinities Reveals Pathways Involved with Euryhalinity. Genes (Basel) 2020; 11:genes11070733. [PMID: 32630108 PMCID: PMC7397140 DOI: 10.3390/genes11070733] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/29/2020] [Accepted: 06/29/2020] [Indexed: 12/13/2022] Open
Abstract
Asian seabass (or commonly known as barramundi), Lates calcarifer, is a bony euryhaline teleost from the Family Latidae, inhabiting nearshore, estuarine, and marine connected freshwaters throughout the tropical Indo-West Pacific region. The species is catadromous, whereby adults spawn in salinities between 28 and 34 ppt at the mouth of estuaries, with resultant juveniles usually moving into brackish and freshwater systems to mature, before returning to the sea to spawn again as adults. The species lives in both marine and freshwater habitats and can move quickly between the two; thus, the species' ability to tolerate changes in salinity makes it a good candidate for studying the salinity acclimation response in teleosts. In this study, the transcriptome of two major osmoregulatory organs (gills and kidneys) of young juvenile Asian seabass reared in freshwater and seawater were compared. The euryhaline nature of Asian seabass was found to be highly pliable and the moldability of the trait was further confirmed by histological analyses of gills and kidneys. Differences in major expression pathways were observed, with differentially expressed genes including those related to osmoregulation, tissue/organ morphogenesis, and cell volume regulation as central to the osmo-adaptive response. Additionally, genes coding for mucins were upregulated specifically under saline conditions, whereas several genes important for growth and development, as well as circadian entrainment were specifically enriched in fish reared in freshwater. Routing of the circadian rhythm mediated by salinity changes could be the initial step in salinity acclimation and possibly migration in euryhaline fish species such as the Asian seabass.
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Tu J, Zhang B, Fang G, Chang W, Zhao Y. Neddylation-mediated Nedd4-2 activation regulates ubiquitination modification of renal NBCe1. Exp Cell Res 2020; 390:111958. [DOI: 10.1016/j.yexcr.2020.111958] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 03/10/2020] [Accepted: 03/11/2020] [Indexed: 12/11/2022]
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Seifter JL. Body Fluid Compartments, Cell Membrane Ion Transport, Electrolyte Concentrations, and Acid-Base Balance. Semin Nephrol 2020; 39:368-379. [PMID: 31300092 DOI: 10.1016/j.semnephrol.2019.04.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Measurements made in the blood, part of the extracellular compartment, are used in the clinical assessment of acid-base disorders; however, intracellular events determine much of the metabolic importance of these disorders. Intracellular and interstitial compartment acid-base balance is complex and varies in different tissues. This review considers the determination of extracellular pH in the context of ion transport processes at the interface of cells and the interstitial fluid, and between epithelial cells lining the transcellular contents of the gastrointestinal and urinary tracts that open to the external environment. A further consideration is the role of these membrane transporters in the generation of acid-base disorders and the associated disruption of electrolyte balance. This review suggests a process of internal and external balance for pH regulation similar to that of potassium, and considers the role of secretory gastrointestinal epithelia and renal epithelia with respect to normal pH homeostasis and clinical disorders. Electroneutrality of electrolytes in the extracellular fluid is a fundamental feature of reciprocal changes in Cl- or non-Cl- anions and HCO3-. Normal mechanisms for protecting cell pH and producing normal gastrointestinal and renal secretions in healthy states also may result in disease when abnormal. In a similar manner, organic anions such as ketoacid anions and lactate, normally transported as fuels between organs, result in acid-base disturbances in disease. Understanding the genomic basis of these transporters may contribute to specific treatments.
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Natochin YV. Principles of Evolution of the Excretory Organs and the System of Homeostasis. J EVOL BIOCHEM PHYS+ 2019. [DOI: 10.1134/s0022093019050077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Zhu H, Liu X, Zhang C, Li Q, An X, Liu S, Wu L, Zhang B, Yuan Y, Xing C. Association of urinary acidification function with the progression of diabetic kidney disease in patients with type 2 diabetes. J Diabetes Complications 2019; 33:107419. [PMID: 31473080 DOI: 10.1016/j.jdiacomp.2019.107419] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 08/10/2019] [Accepted: 08/16/2019] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Although diabetic kidney disease (DKD) has been considered as a glomerulocentric disease in the past few decades, growing evidence demonstrated that tubular damage was indispensable in its pathogenesis and progression. This study was designed to investigate the association of urinary acidification dysfunction with the progression of DKD in type 2 diabetic patients. METHODS Here the urinary acidification functions were measured from 80 participants with renal biopsy-proven DKD. The different kinds of renal tubular transportation dysfunction were analyzed, including the dysfunction of bicarbonate reabsorption, titratable acid secretion, and ammonium secretion. In addition, patients were followed up for 17 (interquartile range, 11-32) months to evaluate the effect of urinary acidification dysfunction in the progression of DKD. RESULTS The most common urinary acidification dysfunction was the disorder of ammonium secretion, accounting for 53.75%. The more proteinuria excretion and the lower glomerular filtration rate (GFR) were observed in the urinary titratable acid disorder group than the normal group, and the same results were obtained for ammonium secretion disorder. Urine titratable acid was positively correlated with eGFR whereas it was inversely correlated with proteinuria, serum creatinine, and BUN. Moreover, 24 h urine protein, serum creatinine, BUN and cystatin C increased from DKD stage II to stage IV, whereas the eGFR and urine titratable acid decreased in the same way. Furthermore, Kaplan-Meier analysis and Cox regression showed that the disorder of titratable acid was an independent risk factor for DKD progression. CONCLUSIONS The dysfunction of urinary titratable acid is a potential biomarker for the severity of proteinuria, eGFR and glomerular lesions in patients with DKD. Moreover, the titratable acid disorder is an independent risk factor of the DKD progression.
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MESH Headings
- Acidosis, Renal Tubular/complications
- Acidosis, Renal Tubular/diagnosis
- Acidosis, Renal Tubular/epidemiology
- Acidosis, Renal Tubular/etiology
- Acids/analysis
- Acids/metabolism
- Adult
- Aged
- Biomarkers/metabolism
- Biomarkers/urine
- Comorbidity
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/epidemiology
- Diabetes Mellitus, Type 2/pathology
- Diabetes Mellitus, Type 2/urine
- Diabetic Nephropathies/complications
- Diabetic Nephropathies/epidemiology
- Diabetic Nephropathies/pathology
- Diabetic Nephropathies/urine
- Disease Progression
- Female
- Glomerular Filtration Rate
- Humans
- Hydrogen-Ion Concentration
- Kidney/metabolism
- Kidney/physiopathology
- Kidney Failure, Chronic/diagnosis
- Kidney Failure, Chronic/epidemiology
- Kidney Failure, Chronic/physiopathology
- Kidney Failure, Chronic/urine
- Male
- Middle Aged
- Prognosis
- Proteinuria/epidemiology
- Proteinuria/etiology
- Proteinuria/urine
- Urine/chemistry
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Affiliation(s)
- Huanhuan Zhu
- Department of Nephrology, the First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Xi Liu
- Department of Nephrology, the First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Chengning Zhang
- Department of Nephrology, the First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Qing Li
- Department of Nephrology, the First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Xiaofei An
- Department of Endocrinology, Jiangsu Province Hospital of Chinese Medicine, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Simeng Liu
- Department of Nephrology, the First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Lin Wu
- Department of Nephrology, the First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Bo Zhang
- Department of Nephrology, the First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China
| | - Yanggang Yuan
- Department of Nephrology, the First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China.
| | - Changying Xing
- Department of Nephrology, the First Affiliated Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China.
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Kashoor I, Batlle D. Proximal renal tubular acidosis with and without Fanconi syndrome. Kidney Res Clin Pract 2019; 38:267-281. [PMID: 31474092 PMCID: PMC6727890 DOI: 10.23876/j.krcp.19.056] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/13/2019] [Accepted: 06/19/2019] [Indexed: 01/02/2023] Open
Abstract
Proximal renal tubular acidosis (RTA) is caused by a defect in bicarbonate (HCO3−) reabsorption in the kidney proximal convoluted tubule. It usually manifests as normal anion-gap metabolic acidosis due to HCO3− wastage. In a normal kidney, the thick ascending limb of Henle’s loop and more distal nephron segments reclaim all of the HCO3− not absorbed by the proximal tubule. Bicarbonate wastage seen in type II RTA indicates that the proximal tubular defect is severe enough to overwhelm the capacity for HCO3− reabsorption beyond the proximal tubule. Proximal RTA can occur as an isolated syndrome or with other impairments in proximal tubular functions under the spectrum of Fanconi syndrome. Fanconi syndrome, which is characterized by a defect in proximal tubular reabsorption of glucose, amino acids, uric acid, phosphate, and HCO3−, can occur due to inherited or acquired causes. Primary inherited Fanconi syndrome is caused by a mutation in the sodium-phosphate cotransporter (NaPi-II) in the proximal tubule. Recent studies have identified new causes of Fanconi syndrome due to mutations in the EHHADH and the HNF4A genes. Fanconi syndrome can also be one of many manifestations of various inherited systemic diseases, such as cystinosis. Many of the acquired causes of Fanconi syndrome with or without proximal RTA are drug-induced, with the list of causative agents increasing as newer drugs are introduced for clinical use, mainly in the oncology field.
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Affiliation(s)
- Ibrahim Kashoor
- Division of Nephrology and Hypertension, Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Daniel Batlle
- Division of Nephrology and Hypertension, Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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Brauner CJ, Shartau RB, Damsgaard C, Esbaugh AJ, Wilson RW, Grosell M. Acid-base physiology and CO2 homeostasis: Regulation and compensation in response to elevated environmental CO2. FISH PHYSIOLOGY 2019. [DOI: 10.1016/bs.fp.2019.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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28
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González SB, Menga G, Raimondi GA, Tighiouart H, Adrogué HJ, Madias NE. Secondary Response to Chronic Respiratory Acidosis in Humans: A Prospective Study. Kidney Int Rep 2018; 3:1163-1170. [PMID: 30197983 PMCID: PMC6127438 DOI: 10.1016/j.ekir.2018.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 05/14/2018] [Accepted: 06/01/2018] [Indexed: 02/07/2023] Open
Abstract
Introduction The magnitude of the secondary response to chronic respiratory acidosis, that is, change in plasma bicarbonate concentration ([HCO3−]) per mm Hg change in arterial carbon dioxide tension (PaCO2), remains uncertain. Retrospective observations yielded Δ[HCO3−]/ΔPaCO2 slopes of 0.35 to 0.51 mEq/l per mm Hg, but all studies have methodologic flaws. Methods We studied prospectively 28 stable outpatients with steady-state chronic hypercapnia. Patients did not have other disorders and were not taking medications that could affect acid−base status. We obtained 2 measurements of arterial blood gases and plasma chemistries within a 10-day period. Results Steady-state PaCO2 ranged from 44.2 to 68.8 mm Hg. For the entire cohort, mean (± SD) steady-state plasma acid−base values were as follows: PaCO2, 52.8 ± 6.0 mm Hg; [HCO3−], 29.9 ± 3.0 mEq/l, and pH, 7.37 ± 0.02. Least-squares regression for steady-state [HCO3−] versus PaCO2 had a slope of 0.476 mEq/l per mm Hg (95% CI = 0.414–0.538, P < 0.01; r = 0.95) and that for steady-state pH versus PaCO2 had a slope of −0.0012 units per mm Hg (95% CI = −0.0021 to −0.0003, P = 0.01; r = −0.47). These data allowed estimation of the 95% prediction intervals for plasma [HCO3−] and pH at different levels of PaCO2 applicable to patients with steady-state chronic hypercapnia. Conclusion In steady-state chronic hypercapnia up to 70 mm Hg, the Δ[HCO3−]/ΔPaCO2 slope equaled 0.48 mEq/l per mm Hg, sufficient to maintain systemic acidity between the mid-normal range and mild acidemia. The estimated 95% prediction intervals enable differentiation between simple chronic respiratory acidosis and hypercapnia coexisting with additional acid−base disorders.
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Affiliation(s)
- Silvia B González
- Department of Pulmonology and Clinical Laboratory, Hospital María Ferrer, Buenos Aires, Argentina
| | - Guillermo Menga
- Department of Pulmonology and Clinical Laboratory, Hospital María Ferrer, Buenos Aires, Argentina
| | - Guillermo A Raimondi
- Department of Pulmonology, Instituto de Investigaciones Neurológicas Raúl Carrea (FLENI), Buenos Aires, Argentina
| | - Hocine Tighiouart
- Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, Massachusetts, USA.,Tufts Clinical and Translational Science Institute, Tufts University, Boston, Massachusetts, USA
| | - Horacio J Adrogué
- Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.,Department of Medicine, Houston Methodist Hospital, Harris Health, Houston, Texas, USA.,Renal Section, Veterans Affairs Medical Center, Houston, Texas, USA
| | - Nicolaos E Madias
- Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts, USA.,Department of Medicine, Division of Nephrology, St. Elizabeth's Medical Center, Boston, Massachusetts, USA
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29
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Fang L, Lee HW, Chen C, Harris AN, Romero MF, Verlander JW, Weiner ID. Expression of the B splice variant of NBCe1 (SLC4A4) in the mouse kidney. Am J Physiol Renal Physiol 2018; 315:F417-F428. [PMID: 29631353 PMCID: PMC6172571 DOI: 10.1152/ajprenal.00515.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 03/07/2018] [Accepted: 03/29/2018] [Indexed: 01/10/2023] Open
Abstract
Sodium-coupled bicarbonate transporters are critical for renal electrolyte transport. The electrogenic, sodium-coupled bicarbonate cotransporter, isoform 1 (NBCe1), encoded by the SLC4A4 geneencoded by the SLC4A4 gene has five multiple splice variants; the A splice variant, NBCe1-A, is the primary basolateral bicarbonate transporter in the proximal convoluted tubule. This study's purpose was to determine if there is expression of additional NBCe1 splice variants in the mouse kidney, their cellular distribution, and their regulation by metabolic acidosis. In wild-type mice, an antibody reactive only to NBCe1-A showed basolateral immunolabel only in cortical proximal tubule (PT) segments, whereas an antibody reactive to all NBCe1 splice variants (pan-NBCe1) showed basolateral immunolabel in PT segments in both the cortex and outer medulla. In mice with NBCe1-A deletion, the pan-NBCe1 antibody showed basolateral PT immunolabel in both the renal cortex and outer stripe of the outer medulla, and immunoblot analysis showed expression of a ~121-kDa protein. RT-PCR of mRNA from NBCe1-A knockout mice directed at splice variant-specific regions showed expression of only NBCe1-B mRNA. In wild-type kidney, RT-PCR confirmed expression of mRNA for the NBCe1-B splice variant and absence of mRNA for the C, D, and E splice variants. Finally, exogenous acid loading increased expression in the proximal straight tubule in the outer stripe of the outer medulla. These studies demonstrate that the NBCe1-B splice variant is present in the PT, and its expression increases in response to exogenous acid loading, suggesting it participates in the PT contribution to acid-base homeostasis.
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Affiliation(s)
- Lijuan Fang
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine , Gainesville, Florida
| | - Hyun-Wook Lee
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine , Gainesville, Florida
| | - Chao Chen
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine , Gainesville, Florida
| | - Autumn N Harris
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine , Gainesville, Florida
| | - Michael F Romero
- Department of Physiology and Biomedical Engineering, Mayo Clinic , Rochester, Minnesota
| | - Jill W Verlander
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine , Gainesville, Florida
| | - I David Weiner
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine , Gainesville, Florida
- Nephrology and Hypertension Section, North Florida/South Georgia Veterans Health System, Gainesville, Florida
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30
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Rajkumar P, Pluznick JL. Acid-base regulation in the renal proximal tubules: using novel pH sensors to maintain homeostasis. Am J Physiol Renal Physiol 2018; 315:F1187-F1190. [PMID: 30066586 DOI: 10.1152/ajprenal.00185.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The kidneys play a critical role in precisely regulating the composition of the plasma to maintain homeostasis. To achieve this, the kidneys must be able to accurately determine or "sense" the concentration of a wide variety of substances and to make adjustments accordingly. Kidneys face a key challenge in the arena of pH balance, as there is a particularly narrow range over which plasma pH varies in a healthy subject (7.35-7.45) and this pH must constantly be protected against a variety of onslaughts (changes in diet, activity, and even elevation). The proximal tubule, the first segment to come into contact with the forming urine, plays an important role in helping the kidneys to maintain pH homeostasis. Recent studies have identified a number of novel proximal tubule proteins and signaling pathways that work to sense changes in pH and subsequently modulate renal pH regulation. In this review, we will highlight the role of novel players in acid-base homeostasis in the proximal tubule.
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Affiliation(s)
- Premraj Rajkumar
- Department of Physiology, Johns Hopkins University , Baltimore, Maryland.,Recursion Pharmaceuticals, Salt Lake City, Utah
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31
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Seifter JL, Chang HY. Extracellular Acid-Base Balance and Ion Transport Between Body Fluid Compartments. Physiology (Bethesda) 2018; 32:367-379. [PMID: 28814497 DOI: 10.1152/physiol.00007.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 07/05/2017] [Accepted: 07/06/2017] [Indexed: 01/18/2023] Open
Abstract
Clinical assessment of acid-base disorders depends on measurements made in the blood, part of the extracellular compartment. Yet much of the metabolic importance of these disorders concerns intracellular events. Intracellular and interstitial compartment acid-base balance is complex and heterogeneous. This review considers the determinants of the extracellular fluid pH related to the ion transport processes at the interface of cells and the interstitial fluid, and between epithelial cells lining the transcellular contents of the gastrointestinal and urinary tracts that open to the external environment. The generation of acid-base disorders and the associated disruption of electrolyte balance are considered in the context of these membrane transporters. This review suggests a process of internal and external balance for pH regulation, similar to that of potassium. The role of secretory gastrointestinal epithelia and renal epithelia with respect to normal pH homeostasis and clinical disorders are considered. Electroneutrality of electrolytes in the ECF is discussed in the context of reciprocal changes in Cl- or non Cl- anions and [Formula: see text].
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32
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Results, meta-analysis and a first evaluation of U NOxR, the urinary nitrate-to-nitrite molar ratio, as a measure of nitrite reabsorption in experimental and clinical settings. Amino Acids 2018; 50:799-821. [PMID: 29728915 DOI: 10.1007/s00726-018-2573-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 04/19/2018] [Indexed: 02/07/2023]
Abstract
We recently found that renal carbonic anhydrase (CA) is involved in the reabsorption of inorganic nitrite (NO2-), an abundant reservoir of nitric oxide (NO) in tissues and cells. Impaired NO synthesis in the endothelium and decreased NO bioavailability in the circulation are considered major contributors to the development and progression of renal and cardiovascular diseases in different conditions including diabetes. Isolated human and bovine erythrocytic CAII and CAIV can convert nitrite to nitrous acid (HONO) and its anhydride N2O3 which, in the presence of thiols (RSH), are further converted to S-nitrosothiols (RSNO) and NO. Thus, CA may be responsible both for the homeostasis of nitrite and for its bioactivation to RSNO/NO. We hypothesized that enhanced excretion of nitrite in the urine may contribute to NO-related dysfunctions in the renal and cardiovascular systems, and proposed the urinary nitrate-to-nitrite molar ratio, i.e., UNOxR, as a measure of renal CA-dependent excretion of nitrite. Based on results from clinical and experimental animal studies, here, we report on a first evaluation of UNOxR. We determined UNOxR values in preterm neonates, healthy children, and adults, in children suffering from type 1 diabetes mellitus (T1DM) or Duchenne muscular dystrophy (DMD), in elderly subjects suffering from chronic rheumatic diseases, type 2 diabetes mellitus (T2DM), coronary artery disease (CAD), or peripheral arterial occlusive disease (PAOD). We also determined UNOxR values in healthy young men who ingested isosorbide dinitrate (ISDN), pentaerythrityl tetranitrate (PETN), or inorganic nitrate. In addition, we tested the utility of UNOxR in two animal models, i.e., the LEW.1AR1-iddm rat, an animal model of human T1DM, and the APOE*3-Leiden.CETP mice, a model of human dyslipidemia. Mean UNOxR values were lower in adult patients with rheumatic diseases (187) and in T2DM patients of the DALI study (74) as compared to healthy elderly adults (660) and healthy young men (1500). The intra- and inter-variabilities of UNOxR were of the order of 50% in young and elderly healthy subjects. UNOxR values were lower in black compared to white boys (314 vs. 483, P = 0.007), which is in line with reported lower NO bioavailability in black ethnicity. Mean UNOxR values were lower in DMD (424) compared to healthy (730) children, but they were higher in T1DM children (1192). ISDN (3 × 30 mg) decreased stronger UNOxR compared to PETN (3 × 80 mg) after 1 day (P = 0.046) and after 5 days (P = 0.0016) of oral administration of therapeutically equivalent doses. In healthy young men who ingested NaNO3 (0.1 mmol/kg/d), UNOxR was higher than in those who ingested the same dose of NaCl (1709 vs. 369). In LEW.1AR1-iddm rats, mean UNOxR values were lower than in healthy rats (198 vs. 308) and comparable to those in APOE*3-Leiden.CETP mice (151).
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Potential biomarkers of tissue hypoxia during acute hemodilutional anemia in cardiac surgery: A prospective study to assess tissue hypoxia as a mechanism of organ injury. Can J Anaesth 2018; 65:901-913. [DOI: 10.1007/s12630-018-1140-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 03/15/2018] [Accepted: 03/16/2018] [Indexed: 02/08/2023] Open
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Lewis L, Kwong RWM. Zebrafish as a Model System for Investigating the Compensatory Regulation of Ionic Balance during Metabolic Acidosis. Int J Mol Sci 2018; 19:E1087. [PMID: 29621145 PMCID: PMC5979485 DOI: 10.3390/ijms19041087] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 03/25/2018] [Accepted: 04/02/2018] [Indexed: 12/16/2022] Open
Abstract
Zebrafish (Danio rerio) have become an important model for integrative physiological research. Zebrafish inhabit a hypo-osmotic environment; to maintain ionic and acid-base homeostasis, they must actively take up ions and secrete acid to the water. The gills in the adult and the skin at larval stage are the primary sites of ionic regulation in zebrafish. The uptake of ions in zebrafish is mediated by specific ion transporting cells termed ionocytes. Similarly, in mammals, ion reabsorption and acid excretion occur in specific cell types in the terminal region of the renal tubules (distal convoluted tubule and collecting duct). Previous studies have suggested that functional regulation of several ion transporters/channels in the zebrafish ionocytes resembles that in the mammalian renal cells. Additionally, several mechanisms involved in regulating the epithelial ion transport during metabolic acidosis are found to be similar between zebrafish and mammals. In this article, we systemically review the similarities and differences in ionic regulation between zebrafish and mammals during metabolic acidosis. We summarize the available information on the regulation of epithelial ion transporters during acidosis, with a focus on epithelial Na⁺, Cl- and Ca2+ transporters in zebrafish ionocytes and mammalian renal cells. We also discuss the neuroendocrine responses to acid exposure, and their potential role in ionic compensation. Finally, we identify several knowledge gaps that would benefit from further study.
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Affiliation(s)
- Lletta Lewis
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada.
| | - Raymond W M Kwong
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada.
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35
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Sheikh IA, Malik A, AlBasri SFM, Beg MA. In silico identification of genes involved in chronic metabolic acidosis. Life Sci 2018; 192:246-252. [PMID: 29138116 DOI: 10.1016/j.lfs.2017.11.014] [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: 09/28/2017] [Accepted: 11/10/2017] [Indexed: 10/18/2022]
Abstract
AIMS Chronic metabolic acidosis (CMA) refers to increased plasma acidity due to disturbed acid-base equilibrium in human body. CMA leads to many dysfunctions including disorders of intestinal metabolism and barrier functions. The human body responds to these intestinal dysfunctions by creating a compensatory mechanism at genomic level in intestinal epithelial cells. This study was to identify the molecular pathways involved in metabolic dysfunction and compensatory adaptations in intestinal epithelium during CMA. MAIN METHODS In silico approaches were utilized to characterize a set of 88 differentially expressed genes (DEGs) from intestinal cells of rat CMA model. Interaction networks were constructed for DEGs by GeneMANIA and hub genes as well as enriched clusters in the network were screened using GLay. Gene Ontology (GO) was used for enriching functions in each cluster. KEY FINDINGS Four gene hubs, i.e., trefoil factor 1, 5-hydroxytryptamine (serotonin) receptor 5a, solute carrier family 6 (neurotransmitter transporter), member 11, and glutamate receptor, ionotropic, n-methyl d-aspartate 2b, exhibiting the highest node degree were predicted. Six biologically related gene clusters were also predicted. Functional enrichment of GO terms predicted neurological processes such as neurological system process regulation and nerve impulse transmission which are related to negative and positive regulation of digestive system processes., intestinal motility and absorption and maintenance of gastrointestinal epithelium. SIGNIFICANCE The study predicted several important genomic pathways that potentially play significant roles in metabolic disruptions or compensatory adaptations of intestinal epithelium induced by CMA. The results provide a further insight into underlying molecular mechanisms associated with CMA.
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Affiliation(s)
- Ishfaq A Sheikh
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.
| | - Adeel Malik
- Perdana University Centre for Bioinformatics, MARDI Complex, Jalan MAEPS Perdana, 43400 Serdang, Selangor, Malaysia
| | - Sameera F M AlBasri
- Department of Obstetrics and Gynecology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohd A Beg
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
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Polymorphisms in Renal Ammonia Metabolism Genes Correlate With 24-Hour Urine pH. Kidney Int Rep 2017; 2:1111-1121. [PMID: 29270519 PMCID: PMC5733879 DOI: 10.1016/j.ekir.2017.06.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 05/23/2017] [Accepted: 06/14/2017] [Indexed: 11/24/2022] Open
Abstract
Introduction Urine pH is critical for net acid and solute excretion, but the genetic factors that contribute to its regulation are incompletely understood. Methods We tested the association of single nucleotide polymorphisms (SNPs) from 16 genes related to ammonia (NH3) metabolism (15 biological candidates selected a priori, 1 selected from a previous genome-wide association study analysis) to that of 24-hour urine pH in 2493 individuals of European descent across 2 different cohorts using linear regression, adjusting for age, sex, and body mass index. Results Of 2871 total SNPs in these genes, 13 SNPs in ATP6V0A4 (a4 subunit of hydrogen− adenosine triphosphatase), SLC9A3 (sodium/hydrogen exchanger, isoform 3), and RHCG (Rhesus C glycoprotein), and 12 SNPs from insulin-like growth factor binding protein 7 (IGFBP7) had a meta-analysis P value <0.01 in the joint analysis plus a consistent direction of effect and at a least suggestive association (P < 0.1) in both cohorts. The maximal effect size (in pH units) for each additional minor allele of the identified SNPs was −0.13 for IGFBP7, −0.08 for ATP6V0A4, 0.06 for RHCG, and −0.06 for SLC9A3; SNP rs34447434 in IGFBP7 had the lowest meta-analysis P value (P = 7.1 × 10−8). After adjusting for net alkali absorption, urine pH remained suggestively associated with multiple SNPs in IGFBP, 1 SNP in ATP6V0A4, and a new SNP in GLS (phosphate-dependent glutaminase). Discussion Overall, these findings suggest that variants in common genes involved in ammonia metabolism may substantively contribute to basal urine pH regulation. These variations might influence the likelihood of developing disease conditions associated with altered urine pH, such as uric acid or calcium phosphate kidney stones.
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Abstract
Acid-base homeostasis is critical to maintenance of normal health. Renal ammonia excretion is the quantitatively predominant component of renal net acid excretion, both under basal conditions and in response to acid-base disturbances. Although titratable acid excretion also contributes to renal net acid excretion, the quantitative contribution of titratable acid excretion is less than that of ammonia under basal conditions and is only a minor component of the adaptive response to acid-base disturbances. In contrast to other urinary solutes, ammonia is produced in the kidney and then is selectively transported either into the urine or the renal vein. The proportion of ammonia that the kidney produces that is excreted in the urine varies dramatically in response to physiological stimuli, and only urinary ammonia excretion contributes to acid-base homeostasis. As a result, selective and regulated renal ammonia transport by renal epithelial cells is central to acid-base homeostasis. Both molecular forms of ammonia, NH3 and NH4+, are transported by specific proteins, and regulation of these transport processes determines the eventual fate of the ammonia produced. In this review, we discuss these issues, and then discuss in detail the specific proteins involved in renal epithelial cell ammonia transport.
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Affiliation(s)
- I David Weiner
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida College of Medicine, Gainesville, Florida; and Nephrology and Hypertension Section, North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Jill W Verlander
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida College of Medicine, Gainesville, Florida; and Nephrology and Hypertension Section, North Florida/South Georgia Veterans Health System, Gainesville, Florida
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Satoh N, Suzuki M, Nakamura M, Suzuki A, Horita S, Seki G, Moriya K. Functional coupling of V-ATPase and CLC-5. World J Nephrol 2017; 6:14-20. [PMID: 28101447 PMCID: PMC5215204 DOI: 10.5527/wjn.v6.i1.14] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 10/04/2016] [Accepted: 11/02/2016] [Indexed: 02/06/2023] Open
Abstract
Dent’s disease is an X-linked renal tubulopathy characterized by low molecular weight proteinuria, hypercalciuria and progressive renal failure. Disease aetiology is associated with mutations in the CLCN5 gene coding for the electrogenic 2Cl-/H+ antiporter chloride channel 5 (CLC-5), which is expressed in the apical endosomes of renal proximal tubules with the vacuolar type H+-ATPase (V-ATPase). Initially identified as a member of the CLC family of Cl- channels, CLC-5 was presumed to provide Cl- shunt into the endosomal lumen to dissipate H+ accumulation by V-ATPase, thereby facilitating efficient endosomal acidification. However, recent findings showing that CLC-5 is in fact not a Cl- channel but a 2Cl-/H+ antiporter challenged this classical shunt model, leading to a renewed and intense debate on its physiological roles. Cl- accumulation via CLC-5 is predicted to play a critical role in endocytosis, as illustrated in mice carrying an artificial Cl- channel mutation E211A that developed defective endocytosis but normal endosomal acidification. Conversely, a recent functional analysis of a newly identified disease-causing Cl- channel mutation E211Q in a patient with typical Dent’s disease confirmed the functional coupling between V-ATPase and CLC-5 in endosomal acidification, lending support to the classical shunt model. In this editorial, we will address the current recognition of the physiological role of CLC-5 with a specific focus on the functional coupling of V-ATPase and CLC-5.
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Lee HW, Handlogten ME, Osis G, Clapp WL, Wakefield DN, Verlander JW, Weiner ID. Expression of sodium-dependent dicarboxylate transporter 1 (NaDC1/SLC13A2) in normal and neoplastic human kidney. Am J Physiol Renal Physiol 2016; 312:F427-F435. [PMID: 27927654 PMCID: PMC5374311 DOI: 10.1152/ajprenal.00559.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 11/15/2016] [Accepted: 12/05/2016] [Indexed: 12/21/2022] Open
Abstract
Regulated dicarboxylate transport is critical for acid-base homeostasis, prevention of calcium nephrolithiasis, regulation of collecting duct sodium chloride transport, and the regulation of blood pressure. Although luminal dicarboxylate reabsorption via NaDC1 (SLC13A2) is believed to be the primary mechanism regulating renal dicarboxylate transport, the specific localization of NaDC1 in the human kidney is currently unknown. This study's purpose was to determine NaDC1's expression in normal and neoplastic human kidneys. Immunoblot analysis demonstrated NaDC1 expression with an apparent molecular weight of ~61 kDa. Immunohistochemistry showed apical NaDC1 immunolabel in the proximal tubule of normal human kidney tissue; well-preserved proximal tubule brush border was clearly labeled. Apical NaDC1 expression was evident throughout the entire proximal tubule, including the initial proximal convoluted tubule, as identified by origination from the glomerular tuft, and extending through the terminal of the proximal tubule, the proximal straight tubule in the outer medulla. We confirmed proximal tubule localization by colocalization with the proximal tubule specific protein, NBCe1. NaDC1 immunolabel was not detected other than in the proximal tubule. In addition, NaDC1 immunolabel was not detected in tumors of presumed proximal tubule origin, clear cell and papillary renal cell carcinoma, or in tumors of nonproximal tubule origin, oncocytoma and chromophobe carcinoma. In summary, 1) in the human kidney, apical NaDC1 immunolabel is present throughout the entire proximal tubule, and is not detectable in other renal cells; and 2) NaDC1 immunolabel is not present in renal tumors. These studies provide important information regarding NaDC1's role in human dicarboxylate metabolism.
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Affiliation(s)
- Hyun-Wook Lee
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Mary E Handlogten
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Gunars Osis
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - William L Clapp
- Department of Pathology, University of Florida College of Medicine, Gainesville, Florida; and
| | - Dara N Wakefield
- Department of Pathology, University of Florida College of Medicine, Gainesville, Florida; and
| | - Jill W Verlander
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - I David Weiner
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida College of Medicine, Gainesville, Florida; .,Nephrology and Hypertension Section, Gainesville Veterans Affairs Medical Center, Gainesville, Florida
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Klootwijk E, Dufek S, Issler N, Bockenhauer D, Kleta R. Pathophysiology, current treatments and future targets in hereditary forms of renal Fanconi syndrome. Expert Opin Orphan Drugs 2016. [DOI: 10.1080/21678707.2017.1259560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
| | - Stephanie Dufek
- Centre for Nephrology, University College London, London, UK
| | - Naomi Issler
- Centre for Nephrology, University College London, London, UK
| | | | - Robert Kleta
- Centre for Nephrology, University College London, London, UK
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Donahue M, Briguori C. Renal Insufficiency and the Impact of Contrast Agents. Interv Cardiol 2016. [DOI: 10.1002/9781118983652.ch27] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Michael Donahue
- Laboratory of Interventional Cardiology and Department of Cardiology; Clinica Mediterranea; Naples Italy
| | - Carlo Briguori
- Laboratory of Interventional Cardiology and Department of Cardiology; Clinica Mediterranea; Naples Italy
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Abstract
All animals are characterized by steep gradients of Na(+) and K(+) across the plasma membrane, and in spite of their highly similar chemical properties, the ions can be distinguished by numerous channels and transporters. The gradients are generated by the Na(+),K(+)-ATPase, or sodium pump, which pumps out Na(+) and takes up K(+) at the expense of the chemical energy from ATP. Because the membrane is more permeable to K(+) than to Na(+), the uneven ion distribution causes a transmembrane voltage difference, and this membrane potential forms the basis for the action potential and for much of the neuronal signaling in general. The potential energy stored in the concentration gradients is also used to drive a large number of the secondary transporters responsible for transmembrane carriage of solutes ranging from sugars, amino acids, and neurotransmitters to inorganic ions such as chloride, inorganic phosphate, and bicarbonate. Furthermore, Na(+) and K(+) themselves are important enzymatic cofactors that typically lower the energy barrier of substrate binding.In this chapter, we describe the roles of Na(+) and K(+) in the animal cell with emphasis on the creation and usage of the steep gradients across the membrane. More than 50 years of Na(+),K(+)-ATPase research has revealed many details of the molecular machinery and offered insights into how the pump is regulated by post-translational modifications and specific drugs.
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Affiliation(s)
- Michael Jakob Voldsgaard Clausen
- Centre for Structural Biology, Department of Molecular Biology and Genetics, University of Aarhus, Science Park, Gustav Wieds Vej 10c, Aarhus C, Denmark,
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Osis G, Handlogten ME, Lee HW, Hering-Smith KS, Huang W, Romero MF, Verlander JW, Weiner ID. Effect of NBCe1 deletion on renal citrate and 2-oxoglutarate handling. Physiol Rep 2016; 4:e12778. [PMID: 27117802 PMCID: PMC4848728 DOI: 10.14814/phy2.12778] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 03/29/2016] [Accepted: 04/01/2016] [Indexed: 12/03/2022] Open
Abstract
UNLABELLED The bicarbonate transporter, NBCe1 (SLC4A4), is necessary for at least two components of the proximal tubule contribution to acid-base homeostasis, filtered bicarbonate reabsorption, and ammonia metabolism. This study's purpose was to determine NBCe1's role in a third component of acid-base homeostasis, organic anion metabolism, by studying mice with NBCe1 deletion. Because NBCe1 deletion causes metabolic acidosis, we also examined acid-loaded wild-type adult mice to determine if the effects of NBCe1 deletion were specific to NBCe1 deletion or were a non-specific effect of the associated metabolic acidosis. Both NBCe1 KO and acid-loading decreased citrate excretion, but in contrast to metabolic acidosis alone, NBCe1 KO decreased expression of the apical citrate transporter, NaDC-1. Thus, NBCe1 expression is necessary for normal NaDC-1 expression, and NBCe1 deletion induces a novel citrate reabsorptive pathway. Second, NBCe1 KO increased 2-oxoglutarate excretion. This could not be attributed to the metabolic acidosis as experimental acidosis decreased excretion. Increased 2-oxoglutarate excretion could not be explained by changes in plasma 2-oxoglutarate levels, the glutaminase I or the glutaminase II generation pathways, 2-oxoglutarate metabolism, its putative apical 2-oxoglutarate transporter, OAT10, or its basolateral transporter, NaDC-3. IN SUMMARY (1) NBCe1 is necessary for normal proximal tubule NaDC-1 expression; (2) NBCe1 deletion results in stimulation of a novel citrate reabsorptive pathway; and (3) NBCe1 is necessary for normal 2-oxoglutarate metabolism through mechanisms independent of expression of known transport and metabolic pathways.
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Affiliation(s)
- Gunars Osis
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Mary E Handlogten
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Hyun-Wook Lee
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | | | - Weitao Huang
- Renal Division, Tulane University College of Medicine, New Orleans, Louisiana
| | - Michael F Romero
- Department of Physiology & Biomedical Engineering and Nephrology & Hypertension, Mayo Clinic College Of Medicine, Rochester, Minnesota
| | - Jill W Verlander
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - I David Weiner
- Division of Nephrology, Hypertension and Renal Transplantation, University of Florida College of Medicine, Gainesville, Florida Nephrology and Hypertension Section, North Florida/South Georgia Veterans Health System, Gainesville, Florida
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Chronic Metabolic Acidosis Activates Renal Tubular Sodium Chloride Cotransporter through Angiotension II-dependent WNK4-SPAK Phosphorylation Pathway. Sci Rep 2016; 6:18360. [PMID: 26728390 PMCID: PMC4700450 DOI: 10.1038/srep18360] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 11/16/2015] [Indexed: 12/30/2022] Open
Abstract
The mechanism by which chronic metabolic acidosis (CMA) regulates sodium (Na(+))-chloride (Cl(-)) cotransporter (NCC) in the renal distal convoluted tubules remains unexplored. We examined the role of STE20/SPS1-related proline/alanine-rich kinase (SPAK) and with-no-lysine kinase 4 (WNK4) on expression of NCC in mouse models of CMA. CMA was induced by NH4Cl in wild type mice (WTA mice), SPAK, and WNK4 knockout mice. The quantities of Ncc mRNA, expression of total NCC, phosphorylated (p)-NCC, SPAK and WNK4 in the kidneys as well as NCC inhibition with hydrochlorothiazide and Na(+) balance were evaluated. Relative to WT mice, WTA mice had similar levels of Ncc mRNA, but increased expression of total and p-NCC, SPAK, and WNK4 and an exaggerated response to hydrochlorothiazide which could not be observed in SPAK or WNK4 knockout mice with CMA. In WTA mice, increased plasma renin activity, aldosterone and angiotensin II concentrations accompanied by a significantly negative Na(+) balance. High Na(+) diet abolished the enhanced NCC expression in WTA mice. Furthermore, an angiotensin II type 1 receptor blocker rather than a mineralocorticoid receptor antagonist exerted a marked inhibition on Na(+) reabsorption and NCC phosphorylation in WTA mice. CMA increases WNK4-SPAK-dependent NCC phosphorylation and appears to be secondary to previous natriuresis with volume-dependent angiotensin II activation.
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Hu MY, Hwang PP, Tseng YC. Recent advances in understanding trans-epithelial acid-base regulation and excretion mechanisms in cephalopods. Tissue Barriers 2015; 3:e1064196. [PMID: 26716070 DOI: 10.1080/21688370.2015.1064196] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 06/09/2015] [Accepted: 06/15/2015] [Indexed: 01/17/2023] Open
Abstract
Cephalopods have evolved complex sensory systems and an active lifestyle to compete with fish for similar resources in the marine environment. Their highly active lifestyle and their extensive protein metabolism has led to substantial acid-base regulatory abilities enabling these organisms to cope with CO2 induced acid-base disturbances. In convergence to teleost, cephalopods possess an ontogeny-dependent shift in ion-regulatory epithelia with epidermal ionocytes being the major site of embryonic acid-base regulation and ammonia excretion, while gill epithelia take these functions in adults. Although the basic morphology and excretory function of gill epithelia in cephalopods were outlined almost half a century ago, modern immunohistological and molecular techniques are bringing new insights to the mechanistic basis of acid-base regulation and excretion of nitrogenous waste products (e.g. NH3/NH4 (+)) across ion regulatory epithelia of cephalopods. Using cephalopods as an invertebrate model, recent findings reveal partly conserved mechanisms but also novel aspects of acid-base regulation and nitrogen excretion in these exclusively marine animals. Comparative studies using a range of marine invertebrates will create a novel and exciting research direction addressing the evolution of pH regulatory and excretory systems.
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Affiliation(s)
- Marian Y Hu
- Institute of Physiology; Christian-Albrechts University Kiel ; Kiel, Germany ; Institute of Cellular and Organismic Biology; Academia Sinica ; Taipei City, Taiwan
| | - Pung-Pung Hwang
- Institute of Cellular and Organismic Biology; Academia Sinica ; Taipei City, Taiwan
| | - Yung-Che Tseng
- Department of Life Science; National Taiwan Normal University ; Taipei City, Taiwan
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Guan SS, Sheu ML, Wu CT, Chiang CK, Liu SH. ATP synthase subunit-β down-regulation aggravates diabetic nephropathy. Sci Rep 2015; 5:14561. [PMID: 26449648 PMCID: PMC4598833 DOI: 10.1038/srep14561] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 09/03/2015] [Indexed: 01/14/2023] Open
Abstract
In this study, we investigated the role of ATP synthase subunit-β (ATP5b) in diabetic nephropathy. Histopathological changes, fibrosis, and protein expressions of α-smooth muscle actin (α-SMA), advanced glycation end-products (AGEs), and ATP5b were obviously observed in the kidneys of db/db diabetic mice as compared with the control db/m(+) mice. The increased ATP5b expression was majorly observed in diabetic renal tubules and was notably observed to locate in cytoplasm of tubule cells, but no significant increase of ATP5b in diabetic glomeruli. AGEs significantly increased protein expression of ATP5b and fibrotic factors and decreased ATP content in cultured renal tubular cells via an AGEs-receptor for AGEs (RAGE) axis pathway. Oxidative stress was also induced in diabetic kidneys and AGEs-treated renal tubular cells. The increase of ATP5b and CTGF protein expression in AGEs-treated renal tubular cells was reversed by antioxidant N-acetylcysteine. ATP5b-siRNA transfection augmented the increased protein expression of α-SMA and CTGF and CTGF promoter activity in AGEs-treated renal tubular cells. The in vivo ATP5b-siRNA delivery significantly enhanced renal fibrosis and serum creatinine in db/db mice with ATP5b down-regulation. These findings suggest that increased ATP5b plays an important adaptive or protective role in decreasing the rate of AGEs-induced renal fibrosis during diabetic condition.
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Affiliation(s)
- Siao-Syun Guan
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Institute of Nuclear Energy Research, Atomic Energy Council, Executive Yuan, Taoyuan, Taiwan
| | - Meei-Ling Sheu
- Biomedical Sciences, College of Life Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Cheng-Tien Wu
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chih-Kang Chiang
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Departments of Integrated Diagnostics &Therapeutics and Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Shing-Hwa Liu
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan.,Department of Pediatrics, National Taiwan University Hospital, Taipei, Taiwan
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Aquaporin 1 Is Involved in Acid Secretion by Ionocytes of Zebrafish Embryos through Facilitating CO2 Transport. PLoS One 2015; 10:e0136440. [PMID: 26287615 PMCID: PMC4546062 DOI: 10.1371/journal.pone.0136440] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 08/04/2015] [Indexed: 12/29/2022] Open
Abstract
Mammalian aquaporin 1 (AQP1) is well known to function as a membrane channel for H2O and CO2 transport. Zebrafish AQP1a.1 (the homologue of mammalian AQP1) was recently identified in ionocytes of embryos; however its role in ionocytes is still unclear. In this study, we hypothesized that zebrafish AQP1a.1 is involved in the acid secretion by ionocytes through facilitating H2O and CO2 diffusion. A real-time PCR showed that mRNA levels of AQP1a.1 in embryos were induced by exposure to 1% CO2 hypercapnia for 3 days. In situ hybridization and immunohistochemistry showed that the AQP1a.1 transcript was highly expressed by acid-secreting ionocytes, i.e., H+-ATPase-rich (HR) cells. A scanning ion-selective electrode technique (SIET) was applied to analyze CO2-induced H+ secretion by individual ionocytes in embryos. H+ secretion by HR cells remarkably increased after a transient loading of CO2 (1% for 10 min). AQP1a.1 knockdown with morpholino oligonucleotides decreased the H+ secretion of HR cells by about half and limited the CO2 stimulated increase. In addition, exposure to an AQP inhibitor (PCMB) for 10 min also suppressed CO2-induced H+ secretion. Results from this study support our hypothesis and provide in vivo evidence of the physiological role of AQP1 in CO2 transport.
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Chinigarzadeh A, Muniandy S, Salleh N. Enhanced expression of sodium hydrogen exchanger (NHE)-1, 2 and 4 in the uteri of rat model for post-menopause under phytoestrogen genistein influence. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 40:39-48. [PMID: 26068551 DOI: 10.1016/j.etap.2015.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/23/2015] [Accepted: 05/01/2015] [Indexed: 06/04/2023]
Abstract
Maintaining near normal uterine fluid pH is important for restoring uterine function after menopause. We hypothesized that genistein could restore uterine fluid pH via its effect on NHE expression. This study therefore investigated changes in uterine NHE-1, 2 and 4 expression under genistein influence. Ovariectomized female rats received genistein (25, 50 or 100mg/kg/day) for seven consecutive days. Uteri were harvested and NHE-1, 2 and 4 mRNA expression were analyzed by Real-time PCR while distribution of these transporters' protein was observed by immunohistochemistry. Expression of NHE-1, 2 and 4 mRNA increased with increasing doses of genistein which was antagonized by ICI 182780. Under genistein influence, NHE-1, 2 and 4 proteins were found to be distributed at apical membrane of endometrial luminal epithelia. Enhanced expression of NHE-1, 2 and 4 in ovariectomised rat uteri by genistein might help to restore pH of uterine fluid which could be useful for women after menopause.
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Affiliation(s)
- Asma Chinigarzadeh
- Dept of Physiology, Faculty of Medicine, University of Malaya, 50603 Lembah Pantai, Kuala Lumpur, Malaysia
| | - Sekaran Muniandy
- Dept of Molecular Medicine, Faculty of Medicine, University of Malaya, 50603 Lembah Pantai, Kuala Lumpur, Malaysia
| | - Naguib Salleh
- Dept of Physiology, Faculty of Medicine, University of Malaya, 50603 Lembah Pantai, Kuala Lumpur, Malaysia.
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