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Medina E, Ariceta G, Batlle D. Primary Distal Renal Tubular Acidosis: Toward an Optimal Correction of Metabolic Acidosis. Clin J Am Soc Nephrol 2024:01277230-990000000-00420. [PMID: 38967973 DOI: 10.2215/cjn.0000000000000535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Accepted: 06/28/2024] [Indexed: 07/07/2024]
Abstract
The term classic, type 1 renal tubular acidosis or primary distal renal tubular acidosis is used to designate patients with impaired ability to excrete acid normally in the urine as a result of tubular transport defects involving type A intercalated cells in the collecting duct. The clinical phenotype is largely characterized by the complications of chronic metabolic acidosis (MA): stunted growth, bone abnormalities, and nephrocalcinosis and nephrolithiasis that develop as the consequence of hypercalciuria and hypocitraturia. All these manifestations are preventable with early and sustained correction of MA with alkali therapy. The optimal target for plasma bicarbonate should be as close as possible to the range considered normal by current standards (between 23 and 28 mEq/L.). Most of the benefits of alkali therapy are tangible early in the course of the disease in childhood, but life-long treatment is required to prevent the vast array of complications attributable to chronic MA.
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Affiliation(s)
- Elba Medina
- Division of Nephrology, General Hospital of México, Eduardo Liceaga, México City, México and Master's and PhD Program in Dental and Health Medical Sciences, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gema Ariceta
- Pediatric Nephrology, University Hospital Vall d'Hebron, and Autonomous University of Barcelona, Barcelona, Spain
| | - Daniel Batlle
- Division of Nephrology/Hypertension, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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Cheng J, Wang W. Association of Dietary Acid Load with Nonalcoholic Fatty Liver Disease and Advanced Liver Fibrosis in US Adults: Evidence from NHANES 1999-2018. Risk Manag Healthc Policy 2023; 16:2819-2832. [PMID: 38145208 PMCID: PMC10749110 DOI: 10.2147/rmhp.s437425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 12/10/2023] [Indexed: 12/26/2023] Open
Abstract
Background Evidence for an association between dietary acid load (DAL) and non-alcoholic fatty liver disease (NAFLD) is scarce and controversial. We aimed to address whether an association exists between DAL and NAFLD/advanced liver fibrosis (AHF) among US adults in a nationally representative study. Methods This was a cross-sectional study. We included adult participants from the National Health and Nutrition Examination Survey 1999-2018. Potential renal acid load (PRAL) and estimated net endogenous acid production (NEAP) was calculated from the literature and NAFLD/AHF was diagnosed by noninvasive markers. We comprehensively explored these relationships using multivariate adjusted regression models, restricted cubic spline, stratification analysis, and sensitivity analysis. Results We enrolled a total of 18,855 participants. All DAL metrics were positively and nonlinearly associated with NAFLD (all p-values < 0.0001), whereas NEAPF and NEAPR may be associated with AHF. In the stratified analysis, we found that the correlation between DAL and NAFLD exists in all ages and genders, but the effect of DAL seems to be more obvious in middle-aged, elderly and women. Similarly, we found that the effect of DAL on AHF was more significant in 45-60-year-olds and women. Sensitivity analyses revealed stability of all results. Conclusion DAL including PRAL and NEAP were positively associated with NAFLD in a large nationally representative cross-sectional study. NEAPF and NEAPR may be associated with increased odds of AHF. Adjustment for diet-dependent DAL requires age- and sex-specific strategies. Future prospective studies are needed to validate our findings.
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Affiliation(s)
- Jin Cheng
- Department of Medicine, Wuhan University of Science and Technology, Wuhan, 430000, People’s Republic of China
- Department of Gastroenterology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei, 441021, People’s Republic of China
| | - Wei Wang
- Department of Gastroenterology, Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, Hubei, 441021, People’s Republic of China
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Bertholet-Thomas A, Manso-Silván MA, Navas-Serrano V, Guittet C, Joukoff S, Bacchetta J, Boyer O, Rodriguez Portillo M, Granier LA. Bone mineral density and growth changes in patients with distal renal tubular acidosis after two-years treatment with a new alkalizing drug (ADV7103). Nefrologia 2023; 43:458-466. [PMID: 36529656 DOI: 10.1016/j.nefroe.2022.02.012] [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: 09/09/2021] [Accepted: 02/27/2022] [Indexed: 06/17/2023] Open
Abstract
BACKGROUND AND OBJECTIVES ADV7103 is a new prolonged-release treatment for distal renal tubular acidosis (dRTA), containing potassium citrate and potassium bicarbonate. Since acidosis may affect bone mineral contents, the effects of ADV7103 on bone mineral density (BMD) and growth in patients with dRTA over 24 months were evaluated. PATIENTS AND METHODS Thirty patients (24 paediatric patients and 6 adults) were included in an open-label extension study after a phase II/III trial. BMD, measured by densitometry, was assessed at baseline and at 24 months. Growth was evaluated throughout the study. Plasma bicarbonate, parathyroid hormone, 25-hydroxy vitamin D, 1,25-dihydroxy vitamin D, bone alkaline phosphatase, calciuria and citraturia, were also determined. Safety and treatment compliance were evaluated as well. RESULTS After 24 months of treatment with ADV7103, mean spine BMD z-score values significantly increased as compared with baseline (p=0.024). In adults, spine and whole-body densitometry z-scores showed a significant correlation with plasma bicarbonate levels (rS=0.82 and rS=0.97, respectively, p<0.005). There was an increase>0.5 units in z-scores for height and weight in 18% and 36% of the paediatric patients, respectively. With treatment, plasma bicarbonate concentration and calciuria at the different visits were normal in 69-86% and 93-96% patients, respectively. Only nine treatment-related gastrointestinal AEs of mild/moderate severity, were reported in five patients. CONCLUSIONS Two years of ADV7103 treatment improved growth and increased spine BMD. These results suggest that control of acidosis by ADV7103 treatment improves bone parameters.
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Affiliation(s)
- Aurélia Bertholet-Thomas
- Centre de Référence des Maladies Rénales Rares - Néphrogones - Hôpital Femme Mère Enfant, Hospices Civils de Lyon - Filière ORKiD, Bron, France
| | | | | | | | | | - Justine Bacchetta
- Centre de Référence des Maladies Rénales Rares - Néphrogones - Hôpital Femme Mère Enfant, Hospices Civils de Lyon - Filière ORKiD, Bron, France
| | - Olivia Boyer
- Service de Néphrologie Pédiatrique, Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Institut Imagine, Hôpital Necker-Enfants Malades, Université de Paris, France
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Guo J, Cao W, Luo J, Huang R, Xiao Y. A retrospective study of the role of hypercapnia in patients with acromegaly. BMC Pulm Med 2023; 23:186. [PMID: 37244996 DOI: 10.1186/s12890-023-02488-3] [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: 09/14/2022] [Accepted: 05/22/2023] [Indexed: 05/29/2023] Open
Abstract
BACKGROUND Acromegaly is a multisystemic disease characterized by an excessive release of growth hormone (GH) and insulin-like growth factor-1. Obstructive sleep apnea (OSA) is a common consequence of acromegaly, and hypercapnia is frequently observed in patients with acromegaly, OSA, and obesity. However, the effects of hypercapnia on acromegaly remain unknown. This study was designed to investigate whether there are differences in clinical symptoms, sleep variables, and biochemical remission after surgery for acromegaly in patients with OSA with or without hypercapnia. METHODS A retrospective analysis was conducted involving patients with acromegaly and OSA. The pharmacotherapy history for acromegaly before surgery, anthropometric measures, blood gas, sleep monitoring data, and biochemical assays of hypercapnic and eucapnic individuals were collected 1-2 weeks before surgery. Univariate and multivariate logistic regression analyses were performed to determine the risk factors for failed postoperative biochemical remission. RESULTS In this study, 94 patients with OSA and acromegaly were included. Among them, 25 (26.6%) had hypercapnia. The hypercapnic group had higher body mass index (92% vs. 62.3%; p = 0.005) and poorer nocturnal hypoxemia index. No serological differences were found between the two groups. According to the post-surgery GH level, 52 patients (55.3%) reached biochemical remission. Univariate logistic regression analysis revealed that diabetes mellitus (odds ratio [OR], 2.59; 95% confidence interval [CI], 1.02-6.55), instead of hypercapnia (OR, 0.61; 95% CI, 0.24-1.58), was associated with lower remission rates. Patients who received pharmacotherapy for acromegaly before surgery (OR, 0.21; 95% CI, 0.06-0.79) and had higher thyroid-stimulating hormone levels (OR, 0.53; 95% CI, 0.32-0.88) were more likely to have biochemical remission after surgery. Multivariate analysis further showed that only diabetes mellitus (OR, 3.29; 95% CI, 1.15-9.46) and preoperative pharmacotherapy (OR, 0.21; 95% CI, 0.06-0.83) remained significant. Hypercapnia, hormone levels, and sleep indicators had no effect on biochemical remission after surgery. CONCLUSIONS Single-center evidence shows that hypercapnia alone may not be a risk factor for lower biochemical remission rates. Correcting hypercapnia does not appear to be required before surgery. More evidence is needed to further support this conclusion.
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Affiliation(s)
- Junwei Guo
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 1 Shuaifuyuan Street, Dongcheng District, Beijing, 100730, China
| | - Wenhao Cao
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 1 Shuaifuyuan Street, Dongcheng District, Beijing, 100730, China
- Department of Respiratory and Critical Care Medicine, The Central Hospital of Wuhan, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jinmei Luo
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 1 Shuaifuyuan Street, Dongcheng District, Beijing, 100730, China
| | - Rong Huang
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 1 Shuaifuyuan Street, Dongcheng District, Beijing, 100730, China
| | - Yi Xiao
- Department of Respiratory and Critical Care Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, No. 1 Shuaifuyuan Street, Dongcheng District, Beijing, 100730, China.
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Zaki SA, Shanbag P. Metabolic Acidosis in Children: A Literature Review. EUROPEAN MEDICAL JOURNAL 2023. [DOI: 10.33590/emj/10302459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023] Open
Abstract
Metabolic acidosis is characterised by a primary decrease in the serum bicarbonate concentration, a secondary decrease in the arterial partial pressure of CO2, and a reduction in blood pH. Metabolic acidosis, acute or chronic, may have deleterious effects on cellular function and cause increased morbidity and mortality. A systematic review of the available literature was performed to identify data on the prevalence, manifestations, cause, outcomes, and treatment of metabolic acidosis in children. Online databases (Ovid Medline, Embase, and PubMed), commercial search engines (including Google), and chapters on metabolic acidosis in the standard textbooks of paediatrics and medicine were reviewed.
Systematic approach to acute metabolic acidosis starts with proper history taking and examination. This is followed by assessment of acid-base parameters, including pH, partial pressure of CO2, and bicarbonate concentration in arterial blood. Blood gas is needed to differentiate primary metabolic acidosis from compensated respiratory alkalosis. Once the diagnosis of a metabolic acidosis has been confirmed, serum electrolyte values are used to determine the serum anion gap. The various causes of increased and normal anion gap metabolic acidosis have been discussed in the article. The main aim of treatment in metabolic acidosis is to reverse the primary pathophysiology. In acute metabolic acidosis, sodium bicarbonate therapy is not beneficial due to potential complications and is reserved for specific situations. Base therapy is used in chronic metabolic acidosis where it ameliorates many of its untoward effects. Other modalities of treatment of metabolic acidosis include peritoneal or haemodialysis and tris-hydroxymethyl aminomethane.
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Affiliation(s)
- Syed Ahmed Zaki
- Department of Pediatrics, All India Institute of Medical Sciences, Hyderabad, India
| | - Preeti Shanbag
- Sir Jamshedjee Jeejeebhoy Group of Hospital and Grant Medical College, Mumbai, India
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Ulrich EH, Chanchlani R. Impact of Metabolic Acidosis and Alkali Therapy on Linear Growth in Children with Chronic Kidney Disease: What Is the Current Evidence? KIDNEY360 2022; 3:590-596. [PMID: 35721614 PMCID: PMC9136911 DOI: 10.34067/kid.0000072022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 03/09/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Emma H. Ulrich
- Division of Pediatric Nephrology, Department of Pediatrics, University of Alberta, Edmonton, Canada
| | - Rahul Chanchlani
- ICES, Toronto, Canada
- Department of Health Research Methods, Evidence and Impact, McMaster University, Hamilton, Canada
- Division of Pediatric Nephrology, Department of Pediatrics, McMaster University, Hamilton, Canada
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Keramati M, Kheirouri S, Musazadeh V, Alizadeh M. Association of High Dietary Acid Load With the Risk of Cancer: A Systematic Review and Meta-Analysis of Observational Studies. Front Nutr 2022; 9:816797. [PMID: 35419387 PMCID: PMC8997294 DOI: 10.3389/fnut.2022.816797] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 02/21/2022] [Indexed: 01/10/2023] Open
Abstract
Objective This study aimed to determine the relationship between the high dietary acid load (DAL) and the risk of cancer. Methods Five databases of PubMed, Web of Sciences, Scopus, Cochrane Library, and Google Scholar was searched to elicit original studies on humans, up to June 2021. Quality of the articles, risk of bias, and heterogeneity were assessed. A random-effects meta-analysis model was applied to estimate pooled effect size with a 95% confidence interval. Sensitivity analysis was performed using a fixed-effects model. Subgroup analyses were carried out based on gender, age, type of cancer, and type of DAL assessment indicator. Results Seventeen effect sizes from 10 articles were included in the analysis. Overall, individuals with the highest DAL were associated with a 66% increased risk of cancer compared to those with the lowest DAL (p < 0.001]. The risk of cancer increased 41% (p < 0.001) and 53% (p = 0.03) by high PRAL and NEAP, respectively. High DAL was associated with 32% (p < 0.001) and 79% (p < 0.001) increased risk of breast and colorectal cancers, respectively. High DAL was associated with 32% (p = 0.001) and 76% (p = 0.007) increased risk of cancer incident in women and men, respectively. The risk of cancer incident increased 35% (p < 0.001) and 49% (p < 0.001) at age ≤ and > of 50, respectively. Conclusion High DAL may be associated with a higher risk of cancer incidence not only in the whole studied population but also across cancer types, both genders, both DAL assessment indicators, and also among both high- and low-risk age groups for cancer.
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Affiliation(s)
- Majid Keramati
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.,Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Sorayya Kheirouri
- Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Vali Musazadeh
- Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.,Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Alizadeh
- Faculty of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
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Bone mineral density and growth changes in patients with distal renal tubular acidosis after two-years treatment with a new alkalizing drug (ADV7103). Nefrologia 2022. [DOI: 10.1016/j.nefro.2022.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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9
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Park JH, Kim JH, Ahn YH, Kang HG, Ha IS, Cheong HI. Gordon syndrome caused by a CUL3 mutation in a patient with short stature in Korea: a case report. J Pediatr Endocrinol Metab 2022; 35:253-257. [PMID: 34480842 DOI: 10.1515/jpem-2021-0361] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 08/20/2021] [Indexed: 11/15/2022]
Abstract
Objectives: Gordon syndrome (GS), also known as pseudohypoaldosteronism type II, is a rare tubular disease characterized by hypertension, hyperkalemia, and metabolic acidosis. Its causative genes are CUL3, KLHL3, WNK1, and WNK4, and they are associated with varying severity of the disease. Herein, we report the first case of GS caused by a CUL3 mutation in a patient with short stature in Korea.Case presentation: A 7-year-old boy had hypertension, metabolic acidosis, and persistent hyperkalemia, which were initially detected during the evaluation of short stature. He was born small for gestational age at late preterm gestation. Laboratory test findings showed hyperkalemia with low trans-tubular potassium gradient, hyperchloremic metabolic acidosis with a normal anion gap, and low plasma renin levels. Genetic analysis revealed a heterozygous de novo mutation in the CUL3 gene (c.1377+1G > C in intron 9). Thus, a diagnosis of GS was made. The results of the endocrine function test (including growth hormone stimulation tests) were normal. After thiazide treatment, the patient's electrolyte levels were normalized. However, he presented with persistent hypertension and short stature.Conclusions: GS should be considered in children with short stature, hypertension, and hyperkalemia, and early treatment may reduce complications.
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Affiliation(s)
- Ji Hong Park
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Republic of Korea
| | - Ji Hyun Kim
- Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Yo Han Ahn
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Kidney Research Institute, Medical Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hee Gyung Kang
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Kidney Research Institute, Medical Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea
- Wide River Institute of Immunology, Seoul National University, Hongcheon, Republic of Korea
| | - Il Soo Ha
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Republic of Korea
- Kidney Research Institute, Medical Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hae Il Cheong
- Department of Pediatrics, Hallym University Sacred Heart Hospital, Anyang, Republic of Korea
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10
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Carlini AS, Choi W, McCallum NC, Gianneschi NC. pH-Responsive Charge-Conversion Progelator Peptides. ADVANCED FUNCTIONAL MATERIALS 2021; 31:2007733. [PMID: 36530181 PMCID: PMC9757809 DOI: 10.1002/adfm.202007733] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Indexed: 05/18/2023]
Abstract
A simple strategy for generating stimuli-responsive peptide-based hydrogels via charge-conversion of a self-assembling peptide (SAP) is described. These materials are formulated as soluble, polyanionic peptides, containing maleic acid, citraconic acid, or dimethylmaleic acid masking groups on each lysine residue, which do not form assemblies, but instead flow easily through high gauge needles and catheters. Acid-induced mask hydrolysis renews the zwitterionic nature of the peptides with concomitant and rapid self-assembly via β-sheet formation into rehealable hydrogels. The use of different masks enables one to tune pH responsiveness and assembly kinetics. In anticipation of their potential for in vivo hydrogel delivery and use, progelators exhibit hemocompatibility in whole human blood, and their peptide components are shown to be noncytotoxic. Finally, demonstration of stimuli-induced self-assembly for dye sequestration suggests a simple, non-covalent strategy for small molecule encapsulation in a degradable scaffold. In summary, this simple, scalable masking strategy allows for preparation of responsive, dynamic self-assembling biomaterials. This work sets the stage for implementing biodegradable therapeutic hydrogels that assemble in response to physiological, disease-relevant states of acidosis.
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Affiliation(s)
- Andrea S Carlini
- Department of Chemistry & Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
- Department of Chemistry, International Institute for Nanotechnology, Chemistry of Life Processes Institute, and Simpson Querrey Institute, Northwestern University, 2145 Sheridan Rd, Evanston, Illinois 60208, USA
| | - Wonmin Choi
- Department of Chemistry, International Institute for Nanotechnology, Chemistry of Life Processes Institute, and Simpson Querrey Institute, Northwestern University, 2145 Sheridan Rd, Evanston, Illinois 60208, USA
| | - Naneki C McCallum
- Department of Chemistry, International Institute for Nanotechnology, Chemistry of Life Processes Institute, and Simpson Querrey Institute, Northwestern University, 2145 Sheridan Rd, Evanston, Illinois 60208, USA
| | - Nathan C Gianneschi
- Department of Chemistry & Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
- Department of Chemistry, International Institute for Nanotechnology, Chemistry of Life Processes Institute, and Simpson Querrey Institute, Northwestern University, 2145 Sheridan Rd, Evanston, Illinois 60208, USA
- Department of Materials Science & Engineering, Department of Biomedical Engineering, and Pharmacology, Northwestern University, 2145 Sheridan Rd, Evanston, Illinois 60208, USA
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Makarevich PI, Efimenko AY, Tkachuk VA. Biochemical Regulation of Regenerative Processes by Growth Factors and Cytokines: Basic Mechanisms and Relevance for Regenerative Medicine. BIOCHEMISTRY (MOSCOW) 2020; 85:11-26. [PMID: 32079514 DOI: 10.1134/s0006297920010022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Regenerative medicine that had emerged as a scientific and medical discipline at end of 20th century uses cultured cells and tissue-engineered structures for transplantation into human body to restore lost or damaged organs. However, practical achievements in this field are far from the promising results obtained in laboratory experiments. Searching for new directions has made apparent that successful solution of practical problems is impossible without understanding the fundamental principles of the regulation of development, renewal, and regeneration of human tissues. These aspects have been extensively investigated by cell biologists, physiologists, and biochemists working in a specific research area often referred to as regenerative biology. It is known that during regeneration, growth factors, cytokines, and hormones act beyond the regulation of individual cell functions, but rather activate specific receptor systems and control pivotal tissue repair processes, including cell proliferation and differentiation. These events require numerous coordinated stimuli and, therefore, are practically irreproducible using single proteins or low-molecular-weight compounds, i.e., cannot be directed by applying classical pharmacological approaches. Our review summarizes current concepts on the regulatory mechanisms of renewal and regeneration of human tissues with special attention to certain general biological and evolutionary aspects. We focus on the biochemical regulatory mechanisms of regeneration, in particular, the role of growth factors and cytokines and their receptor systems. In a separate section, we discussed practical approaches for activating regeneration using small molecules and stem cell secretome containing a broad repertoire of growth factors, cytokines, peptides, and extracellular vesicles.
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Affiliation(s)
- P I Makarevich
- Lomonosov Moscow State University, Institute for Regenerative Medicine, Medical Research and Education Center, Moscow, 119991, Russia. .,Lomonosov Moscow State University, Faculty of Fundamental Medicine, Moscow, 119991, Russia
| | - A Yu Efimenko
- Lomonosov Moscow State University, Institute for Regenerative Medicine, Medical Research and Education Center, Moscow, 119991, Russia.,Lomonosov Moscow State University, Faculty of Fundamental Medicine, Moscow, 119991, Russia
| | - V A Tkachuk
- Lomonosov Moscow State University, Institute for Regenerative Medicine, Medical Research and Education Center, Moscow, 119991, Russia.,Lomonosov Moscow State University, Faculty of Fundamental Medicine, Moscow, 119991, Russia.,Institute of Experimental Cardiology, National Medical Research Center of Cardiology, Moscow, 121552, Russia
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Liao WH, Suendermann C, Steuer AE, Pacheco Lopez G, Odermatt A, Faresse N, Henneberg M, Langhans W. Aldosterone deficiency in mice burdens respiration and accentuates diet-induced hyperinsulinemia and obesity. JCI Insight 2018; 3:99015. [PMID: 30046010 DOI: 10.1172/jci.insight.99015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 06/08/2018] [Indexed: 12/20/2022] Open
Abstract
Aldosterone synthase inhibitors (ASIs) should alleviate obesity-related cardiovascular and renal problems resulting partly from aldosterone excess, but their clinical use may have limitations. To improve knowledge for the use of ASIs, we investigated physiology in aldosterone synthase-knockout (ASKO) mice. On regular chow diet (CD), ASKO mice ate more and weighed less than WT mice, largely because they hyperventilated to eliminate acid as CO2. Replacing CD with high-fat diet (HFD) lessened the respiratory burden in ASKO mice, as did 12- to 15-hour fasting. The latter eliminated the genotype differences in respiratory workload and energy expenditure (EE). Thus, aldosterone deficiency burdened the organism more when the animals ate carbohydrate-rich chow than when they ate a HFD. Chronic HFD exposure further promoted hyperinsulinemia in ASKO mice that contributed to visceral fat accumulation accompanied by reduced lipolysis, thermogenic reprogramming, and the absence of weight-gain-related EE increases. Intracerebroventricular aldosterone supplementation in ASKO mice attenuated the HFD-induced hyperinsulinemia, but did not affect EE, suggesting that the presence of aldosterone increased the body's energetic efficiency, thus counteracting the EE-increasing effect of low insulin. ASIs may therefore cause acid-overload-induced respiratory burden and promote obesity. Their use in patients with preexisting renal and cardiopulmonary diseases might be contraindicated.
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Affiliation(s)
- Wan-Hui Liao
- Physiology and Behavior Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland.,Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,National Center of Competence in Research "Kidney.CH", Switzerland
| | | | - Andrea Eva Steuer
- Department of Forensic Pharmacology and Toxicology, Zurich Institute of Forensic Medicine, University of Zurich, Zurich, Switzerland
| | - Gustavo Pacheco Lopez
- Physiology and Behavior Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland.,Department of Health Sciences, Division of Biological and Health Sciences, Metropolitan Autonomous University (UAM), Lerma, Mexico
| | - Alex Odermatt
- National Center of Competence in Research "Kidney.CH", Switzerland.,Division of Molecular and Systems Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Nourdine Faresse
- Institute of Anatomy, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,National Center of Competence in Research "Kidney.CH", Switzerland
| | - Maciej Henneberg
- Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland.,Biological Anthropology and Comparative Anatomy Unit, University of Adelaide, Australia
| | - Wolfgang Langhans
- Physiology and Behavior Laboratory, Institute of Food, Nutrition and Health, ETH Zurich, Schwerzenbach, Switzerland
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Fathallah-Shaykh S, Drozdz D, Flynn J, Jenkins R, Wesseling-Perry K, Swartz SJ, Wong C, Accomando B, Cox GF, Warady BA. Efficacy and safety of sevelamer carbonate in hyperphosphatemic pediatric patients with chronic kidney disease. Pediatr Nephrol 2018; 33:325-333. [PMID: 28900759 DOI: 10.1007/s00467-017-3787-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 08/08/2017] [Accepted: 08/10/2017] [Indexed: 01/10/2023]
Abstract
BACKGROUND Treatment for hyperphosphatemia in chronic kidney disease (CKD) involves dietary control of phosphorus intake, dialysis, and treatment with oral phosphate binders, none of which were approved by the Federal Food and Drug Administration in pediatric patients at the time of this study. METHODS This was a phase 2, multicenter study (NCT01574326) with a 2-week, randomized, placebo-controlled, fixed-dose period (FDP) followed by a 6-month, single-arm, open-label, dose-titration period (DTP), with the aim to evaluate the safety and efficacy of sevelamer carbonate (SC) in hyperphosphatemic pediatric patients with CKD. Following a 2-4 week screening phase, pediatric patients with a serum phosphorus level higher than age-appropriate levels were randomized to receive either SC or placebo as powder/tablets in 0.4-1.6 g doses, based on body surface area. The primary efficacy outcome was the change in serum phosphorus from baseline to end of the FDP in the SC versus placebo arms (analysis of covariance). The secondary outcome was mean change in serum phosphorus from baseline to end of DTP by treatment group and overall. Treatment-emergent/serious adverse events (AEs) were recorded. RESULTS Of 101 enrolled patients (29 centers), 66 completed the study. The majority of patients were adolescents (74%; mean age 14.1 years) and on dialysis (77%). Renal transplant was the main reason for discontinuation. SC significantly reduced serum phosphorus from baseline levels (7.16 mg/dL) during the FDP compared to placebo (least square mean difference - 0.90 mg/dL, p = 0.001) and during the DTP (- 1.18 mg/dL, p < 0.0001). The safety and tolerability of SC and placebo were similar during the FDP, with patients in both groups reporting mild/moderate gastrointestinal AEs during the DTP. CONCLUSIONS Sevelamer carbonate significantly lowered serum phosphorus levels in hyperphosphatemic children with CKD, with no serious safety concerns identified.
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Affiliation(s)
| | - Dorota Drozdz
- Jagiellonian University Medical College, Krakow, Poland
| | | | | | | | - Sarah J Swartz
- Texas Children's Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Craig Wong
- University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | | | - Gerald F Cox
- Sanofi, Cambridge, MA, USA
- Editas Medicine, Cambridge, MA, USA
| | - Bradley A Warady
- Children's Mercy Kansas City, 2401 Gilham Road, Kansas City, MO, 64108, USA.
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Cibulskis CC, Armbrecht ES. Association of metabolic acidosis with bovine milk-based human milk fortifiers. J Perinatol 2015; 35:115-9. [PMID: 25102321 DOI: 10.1038/jp.2014.143] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/16/2014] [Accepted: 06/20/2014] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To compare the incidence of metabolic acidosis and feeding intolerance associated with powdered or acidified liquid human milk fortifier (HMF). STUDY DESIGN This retrospective study evaluated infants ⩽ 32 weeks gestational age or ⩽ 1500 g birth weight who received human milk with either powdered or acidified liquid HMF (50 consecutively born infants per group). Primary outcomes tracked were metabolic acidosis (base excess less than -4 mmol l(-1) or bicarbonate less than 18 mmol l(-1)), feeding intolerance (gastric residual > 50% feed volume, > 3 loose stools or emesis per day, abdominal tenderness or distention), necrotizing enterocolitis, late-onset infection, death, length of hospital stay and ability to remain on HMF. Demographics, feeding practices, growth parameters and laboratory data were also collected. RESULT Significantly more infants who received acidified liquid HMF developed metabolic acidosis (P < 0.001). Base excess and bicarbonate were both significantly decreased after HMF addition in the liquid HMF group (base excess P = 0.006, bicarbonate P < 0.001). More infants were switched off liquid HMF due to metabolic acidosis or feeding intolerance than those on powdered HMF (P < 0.001). Despite increased protein intake in the liquid HMF group (P = 0.009), both groups had similar enteral caloric intakes with no difference in growth rates between the two groups. There was no significant difference in any of the other primary outcomes. CONCLUSION Infants receiving acidified liquid human milk fortifier were more likely to develop metabolic acidosis and to be switched off HMF than those who received powdered HMF. Growth in the liquid HMF group was no different than the powdered group, despite higher protein intake.
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Affiliation(s)
- C C Cibulskis
- Division of Neonatal-Perinatal Medicine, Department of Pediatrics, Saint Louis University, St Louis, MO, USA
| | - E S Armbrecht
- Saint Louis University Center for Outcomes Research, Saint Louis University, St Louis, MO, USA
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15
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Acid loading stimulates rat glomerular mesangial cells proliferation through Na+–H+ exchanger isoform 1 (NHE1)-dependent pathway. Naunyn Schmiedebergs Arch Pharmacol 2013; 386:563-9. [DOI: 10.1007/s00210-013-0856-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 03/15/2013] [Indexed: 10/27/2022]
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16
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Moya F, Sisk PM, Walsh KR, Berseth CL. A new liquid human milk fortifier and linear growth in preterm infants. Pediatrics 2012; 130:e928-35. [PMID: 22987877 DOI: 10.1542/peds.2011-3120] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES To evaluate the growth, tolerance, and safety of a new ultraconcentrated liquid human milk fortifier (LHMF) designed to provide optimal nutrients for preterm infants receiving human breast milk in a safe, nonpowder formulation. METHODS Preterm infants with a body weight ≤ 1250 g fed expressed and/or donor breast milk were randomized to receive a control powder human milk fortifier (HMF) or a new LHMF for 28 days. When added to breast milk, the LHMF provided ∼20% more protein than the control HMF. Weight, length, head circumference, and serum prealbumin, albumin, blood urea nitrogen, electrolytes, and blood gases were measured. The occurrence of sepsis, necrotizing enterocolitis, and serious adverse events were monitored. RESULTS This multicenter, third party-blinded, randomized controlled, prospective study enrolled 150 infants. Achieved weight and linear growth rate were significantly higher in the LHMF versus control groups (P = .04 and 0.03, respectively). Among infants who adhered closely to the protocol, the LHMF had a significantly higher achieved weight, length, head circumference, and linear growth rate than the control HMF (P = .004, P = .003, P = .04, and P = .01, respectively). There were no differences in measures of feeding tolerance or days to achieve full feeding volumes. Prealbumin, albumin, and blood urea nitrogen were higher in the LHMF group versus the control group (all P < .05). There was no difference in the incidence of confirmed sepsis or necrotizing enterocolitis. CONCLUSIONS Use of a new LHMF in preterm infants instead of powder HMF is safe. Benefits of LHMF include improvements in growth and avoidance of the use of powder products in the NICU.
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Affiliation(s)
- Fernando Moya
- Coastal Carolina Neonatology, Wilmington, North Carolina, USA
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17
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Krupp D, Johner SA, Kalhoff H, Buyken AE, Remer T. Long-term dietary potential renal acid load during adolescence is prospectively associated with indices of nonalcoholic fatty liver disease in young women. J Nutr 2012; 142:313-9. [PMID: 22223573 DOI: 10.3945/jn.111.150540] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD), frequently already present in young subjects, has been linked to reduced growth hormone levels and signaling. Similar hormonal changes occur during metabolic acidosis (MA), which may thus contribute to an increased NAFLD risk. Because subclinical MA can be diet induced, we aimed to examine whether a higher diet-dependent acid load during adolescence is prospectively associated with several currently used NAFLD surrogates in young adulthood. Dietary acidity during adolescence (boys:10-15 y, girls: 9-14 y) was calculated as potential renal acid load (PRAL) from at least three 3-d weighed dietary records according to a published algorithm considering dietary protein and minerals in 145 healthy participants. Routine measurements derived from blood analysis and anthropometric data in participants' young adulthood (18-25 y) were used to determine the NAFLD surrogates alanine-aminotransferase (ALT), hepatic steatosis index (HSI), and fatty liver index (FLI). Sex-stratified linear regression models, adjusted for dietary fiber, saturated fat, protein, and adolescent BMI SD scores, were run with PRAL as the independent variable. Dietary PRAL during puberty was positively associated with ALT (P = 0.02), HSI (P = 0.002), and FLI (P = 0.005) in adult females but not males. Females with an adolescent dietary acid load in the highest tertile had 3.5, 4.4, and 4.5 higher values of ALT, HSI, and FLI as adults, respectively, compared to females with the lowest PRAL. The present findings suggest that higher dietary acidity in adolescence may be prospectively associated with hepatic lipid accumulation in females. Whether this relationship is due to the higher proton load or rather represents an unhealthy dietary pattern requires further investigation.
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Affiliation(s)
- Danika Krupp
- Department of Nutrition and Health, Research Institute of Child Nutrition, Rheinische Friedrich-Wilhelms-University Bonn, Dortmund, Germany.
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18
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Growth-plate cartilage in chronic renal failure. Pediatr Nephrol 2010; 25:643-9. [PMID: 19816714 DOI: 10.1007/s00467-009-1307-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2009] [Revised: 08/05/2009] [Accepted: 08/05/2009] [Indexed: 12/13/2022]
Abstract
Bone growth occurs in the growth-plate cartilage located at the ends of long bones. Changes in the architecture, abnormalities in matrix organization, reduction in protein staining and RNA expression of factors involved in cell signaling have been described in the growth-plate cartilage of nephrectomized animals. These changes can lead to a smaller growth plate associated with decrease in chondrocyte proliferation, delayed hypertrophy, and prolonged initiation of mineralization and vascular invasion. As a result, chronic renal failure can result in stunted body growth and skeletal deformities. Multiple etiologic factors can contribute to impaired bone growth in renal failure, including suboptimal nutrition, metabolic acidosis, and secondary hyperparathyroidism. Recent findings have also shown the tight connection between chondro/osteogenesis, hematopoiesis, and immunogenesis.
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Sharan S, Dupuis A, Hébert D, Levin AV. The effect of oral acetazolamide on weight gain in children. Can J Ophthalmol 2010; 45:41-5. [DOI: 10.3129/i09-198] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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20
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Abstract
Growth may be severely impaired in children with chronic renal insufficiency. Since short stature can have major consequences on quality of life and self-esteem, achieving a 'normal' height is a crucial issue for renal transplant recipients. However, despite successful renal transplantation, the final height attained by most recipients is not the calculated target height. Catch-up growth spurts post-transplantation are usually insufficient to compensate for the retardation in growth that has occurred during the pre-transplant period. Longitudinal growth post-transplantation is therefore influenced by the age at transplantation but also by subsequent allograft function and steroid exposure, both of which interfere with the growth hormone/insulin-like growth factor axis. The management of growth retardation in renal transplant recipients includes adequate nutritional intake, correction of metabolic acidosis, prevention of bone disease, steroid-sparing strategies and a supraphysiological dose of recombinant human growth hormone in selected cases.
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Affiliation(s)
- Jérôme Harambat
- Département de Pédiatrie and Inserm U820, Hôpital Edouard-Herriot and Université Claude-Bernard Lyon 1, Lyon, France
| | - Pierre Cochat
- Département de Pédiatrie and Inserm U820, Hôpital Edouard-Herriot and Université Claude-Bernard Lyon 1, Lyon, France
- Département de Pédiatrie, Unité de Néphrologie Pédiatrique, Hôpital Edouard Herriot, place d’Arsonval, 69437 Lyon, France
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Rajan VR, Mitch WE. Muscle wasting in chronic kidney disease: the role of the ubiquitin proteasome system and its clinical impact. Pediatr Nephrol 2008; 23:527-35. [PMID: 17987322 PMCID: PMC2259254 DOI: 10.1007/s00467-007-0594-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 06/13/2007] [Accepted: 06/14/2007] [Indexed: 02/06/2023]
Abstract
Muscle wasting in chronic kidney disease (CKD) and other catabolic diseases (e.g. sepsis, diabetes, cancer) can occur despite adequate nutritional intake. It is now known that complications of these various disorders, including acidosis, insulin resistance, inflammation, and increased glucocorticoid and angiotensin II production, all activate the ubiquitin-proteasome system (UPS) to degrade muscle proteins. The initial step in this process is activation of caspase-3 to cleave the myofibril into its components (actin, myosin, troponin, and tropomyosin). Caspase-3 is required because the UPS minimally degrades the myofibril but rapidly degrades its component proteins. Caspase-3 activity is easily detected because it leaves a characteristic 14kD actin fragment in muscle samples. Preliminary evidence from several experimental models of catabolic diseases, as well as from studies in patients, indicates that this fragment could be a useful biomarker because it correlates well with the degree of muscle degradation in dialysis patients and in other catabolic conditions.
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Affiliation(s)
- Vik R. Rajan
- Nephrology Division M/S: BCM 285, Baylor College of Medicine, One Baylor, Plaza, Alkek N-520, Houston, TX 77030 USA
| | - William E. Mitch
- Nephrology Division M/S: BCM 285, Baylor College of Medicine, One Baylor, Plaza, Alkek N-520, Houston, TX 77030 USA
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22
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Jamard B, Allard J, Caron P, Corberand JX, Blanchard A, Vargas-Poussou R, El Mahou S, Constantin A, Cantagrel A, Mazières B, Laroche M. Distal renal tubular acidosis and ovalocytosis: a case report. Osteoporos Int 2008; 19:119-22. [PMID: 17690931 DOI: 10.1007/s00198-007-0419-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Accepted: 06/11/2007] [Indexed: 10/23/2022]
Abstract
A 23-year-old man presented with osteoporosis, revealed by femoral fractures, and a history of nephrolithiasis, short stature, metabolic acidosis, hypokalemia and ovalocytosis, a red blood cell abnormality common in malaria endemic regions. Biological investigations led to the diagnosis of type 1 distal renal tubular acidosis (dRTA). Ovalocytosis and dRTA may co-exist in the same patient, since both can originate in mutations of the anion-exchanger 1 (AE1) gene, which codes for band 3, the bicarbonate/chloride exchanger, present in both the red cell membrane and the basolateral membrane of the collecting tubule alpha-intercalated cell.
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Affiliation(s)
- B Jamard
- Department of Rheumatology, University Hospital of Rangueil, Toulouse, France
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23
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Demigné C, Sabboh H, Puel C, Rémésy C, Coxam V. Organic anions and potassium salts in nutrition and metabolism. Nutr Res Rev 2007; 17:249-58. [DOI: 10.1079/nrr200485] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractThe present review examines the importance of dietary organic anions in preventive nutrition. Organic anions are chiefly supplied by plant foods, as partially neutralised K salts such as potassium citrate, potassium malate and, to a lesser extent, oxalate or tartrate salts. Animal products may also supply K anions, essentially as phosphate, but also as lactate as a result of fermentative or maturation processes, but these K salts have little alkalinising significance. Citrate and malate anions are absorbed in the upper digestive tract, while a substantial proportion is probably metabolised in the splanchnic area. Whatever their site of metabolism, these anions finally yield KHCO3which is used by the kidneys to neutralise fixed acidity. This acidity essentially reflects the oxidation of excess S amino acids to sulfate ions, which is mainly related to the dietary protein level. Failure to neutralise acidity leads to low-grade metabolic acidosis, with possible long-term deleterious effects on bone Ca status and on protein status. Furthermore, low-grade acidosis is liable to affect other metabolic processes, such as peroxidation of biological structures. These metabolic disturbances could be connected with the relatively high incidence of osteoporosis and muscle-protein wasting problems observed in ageing individuals in Europe and Northern America. Providing a sufficient supply of K organic anions through fruit and vegetable intake should be recommended, fostering the actual motivational campaigns ('five (or ten) per d') already launched to promote the intake of plant foods rich in complex carbohydrates and various micronutrients.
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Ambühl PM. Posttransplant metabolic acidosis: a neglected factor in renal transplantation? Curr Opin Nephrol Hypertens 2007; 16:379-87. [PMID: 17565282 DOI: 10.1097/mnh.0b013e3281bd8860] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE OF REVIEW The occurrence and pathogenesis of metabolic acidosis after renal transplantation is reviewed. Posttransplant acidosis is shown to be a key mechanism for major metabolic complications in mineral and muscle metabolism, and for anemia, discussed in the context of both acidosis and renal transplantation. RECENT FINDINGS Continuous improvement in kidney transplant survival has shifted attention to long-term outcomes, specifically to disorders linked to cardiovascular disease, physical capacity and quality of life. Metabolic acidosis is gaining growing acceptance as a clinical entity and has occasionally come into focus in the context of renal transplantation. The possible link to metabolic disturbances resulting in impairment of musculoskeletal disorders and physical limitations, however, has not been considered specifically. SUMMARY Available evidence suggests a high prevalence of (compensated) metabolic acidosis after renal transplantation, presenting as low serum bicarbonate and impaired renal acid excretion. This condition is associated with relevant disorders in mineral metabolism and muscle function. Current knowledge about the effects of acidosis on renal electrolyte handling, mineral metabolism and protein synthesis suggests that acid/base derangements contribute to the muscle and bone pathology, as well as anemia, encountered after kidney transplantation. Consequently, posttransplant acidosis may be a relevant factor in the causal pathway of impaired physical capacity observed in this patient group.
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Affiliation(s)
- Patrice M Ambühl
- Department of Nephrology, University Hospital, Zurich, Switzerland.
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25
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Yonemitsu I, Muramoto T, Soma K. The influence of masseter activity on rat mandibular growth. Arch Oral Biol 2007; 52:487-93. [PMID: 17126288 DOI: 10.1016/j.archoralbio.2006.10.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 09/29/2006] [Accepted: 10/15/2006] [Indexed: 10/23/2022]
Abstract
Many studies have shown that mandibular and condylar growth is affected by compressive forces on mandibular bone and the condyle. It has been reported that chondroblastic differentiation and proliferation in chondrocytes play important roles in condylar growth. However, the influence of reduced compressive force on chondroblastic proliferation and mandibular bone formation is not fully understood. Thirty-six 3-week-old male Wistar rats were used in this study. In the experimental group, the masseter muscles were bilaterally resected to evaluate the influence of masticatory force on mandibular and condylar bone morphology. Six weeks after the operation, while the rats were in the pubertal growth stage, lateral X-rays were taken to analyze the skeletal pattern of the mandible. The form of the condyle and the thickness of the chondroblastic layers were evaluated by toluidine blue staining. Chondroblastic proliferation was identified by insulin-like growth factor-1 receptor (IGF-1r) immunostaining and bone resorption of the condyle was assessed by measuring tartrate-resistant acid phosphatase (TRAP) activity. Lateral X-rays of the mandible showed that rats in the experimental group tended to have large mandibular plane angles. The chondroblastic layer in the condyles of the experimental group rats was thinner than in the control group. The expression of IGF-1r immunopositive cells in the experimental group was significantly lower than in the control chondrocytes, and the number of TRAP-positive cells was significantly higher in the condylar bone of the experimental group. We conclude that masseter muscle activity is closely related to mandibular morphology during growth.
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Affiliation(s)
- Ikuo Yonemitsu
- Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
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Abstract
In mammals, statural growth is primarily accomplished by endochondral ossification, which takes place at the growth plate. Growth plate chondrocyte proliferation, hypertrophy/differentiation, apoptosis, and cartilage matrix synthesis all contribute to chondrogenesis or cartilage formation, a process tightly coupled to the simultaneous remodeling of the cartilage into bone at the metaphyseal border of the growth plate. Growth plate chondrogenesis is regulated by the complex interaction of molecular signals acting systemically as well locally within the growth plate. This network is often dysregulated during chronic illnesses, thus resulting in impaired growth plate chondrogenesis and, in turn, growth failure. The principal events responsible for altered growth plate chondrogenesis in chronic illness are inflammation, protein/calorie deprivation, uremia/metabolic acidosis, glucocorticoids, and impaired GH/IGF-I axis.
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Affiliation(s)
- Francesco De Luca
- Section of Endocrinology and Diabetes, St. Christopher's Hospital for Children, Department of Pediatrics, Drexel University College of Medicine, Philadelphia, Pennsylvania 19134, USA.
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Goldberg R, Reshef-Bankai E, Coleman R, Green J, Maor G. Chronic acidosis-induced growth retardation is mediated by proton-induced expression of Gs protein. J Bone Miner Res 2006; 21:703-13. [PMID: 16734385 DOI: 10.1359/jbmr.060210] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED The etiology of skeletal growth retardation accompanying metabolic acidosis is not clear. Using ex vivo models for endochondral ossification, we showed that the cAMP/PKA pathway, probably triggered by proton sensitive G-protein-coupled receptors, is responsible for impaired skeletal growth in acidosis. INTRODUCTION Chronic metabolic acidosis (CMA) is very often accompanied by skeletal growth retardation. We have previously shown in an ex vivo model of endochondral ossification that murine mandibular condyles subjected to acidic conditions exhibit growth retardation accompanied by a decline of insulin-like growth factor-I (IGF-I) and its receptors. PTH-induced ameliorative effects on the CMA-induced growth retardation of the mandibular condyle are partially mediated by protein kinase C (PKC). In this study we explored the mechanisms underlying the acidosis-induced growth retardation; in particular, the involvement of the cyclic adenosine monophosphate/protein kinase A (cAMP/PKA) cellular pathway in the process. MATERIALS AND METHODS Mandibular condyles from neonatal mice or mandibular condyle derived chondrocytes (MCDCs) were incubated for 3 days under either control or acidic conditions or in the presence of cAMP-regulating factors (cAMPrf) such as forskolin, iso-butyl methyl xanthine (IBMX), or 8-Br cAMP. The effects on proliferation and differentiation of the cultures as well as on phosphorylation of cAMP responsive element binding protein (CREB) and increased expression of the alpha subunit, Gs were determined. The intracellular pH was detected using the acridine orange assay. RESULTS Our results show that, under acidic conditions, PKA levels were increased. H89 abolished the adverse effects of acidosis on condylar development and restored IGF-I and IGF-I receptors (IGF-IR) levels. The inhibitory effects of acidosis on proliferation and differentiation of cartilaginous cells were mimicked by cAMPrf. We have also shown that acidosis stimulates activation of Gs trimeric protein and CREB phosphorylation. GDPbetaS--a Gs antagonist--abolished the acidosis-induced condylar growth arrest. Using an acridine orange assay, we showed that the intracellular environment is not acidified under acidic conditions. CONCLUSIONS Our results indicate that the adverse effects of acidosis on skeletal growth centers are mediated at least in part by the cAMP/PKA cellular pathway. We speculate that high proton concentrations exerted by acidosis conditions stimulate proton sensitive G-protein-coupled receptors, which are mediated by the cellular cAMP/PKA pathway and induce skeletal growth retardation.
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Affiliation(s)
- Ruth Goldberg
- Department of Anatomy and Cell Biology, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa
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Torres PU, Prié D, Beck L, Friedlander G. New Therapies for Uremic Secondary Hyperparathyroidism. J Ren Nutr 2006; 16:87-99. [PMID: 16567265 DOI: 10.1053/j.jrn.2006.01.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2005] [Indexed: 11/11/2022] Open
Abstract
Secondary hyperparathyroidism (SHPT) is a common and serious complication of chronic kidney disease (CKD). It affects more than 300,000 end-stage renal disease patients treated by dialysis and probably more than 3 million patients with CKD worldwide. For a long time, traditional therapies for SHPT had consisted of correcting the hypocalcemia using calcium salts and vitamin D derivatives, preventing the hyperphosphatemia by calcium- or aluminum-containing intestinal phosphate binders, and recently by using no metal-containing intestinal phosphate binders; however, these therapies are limited by the occurrence of hypercalcemia, hyperphosphatemia, and the lack of specificity and long-term efficacy. Moreover, surgical parathyroidectomy (PTX), which remains the gold standard therapy, is not exempt from risk. PTX exposes patients to anesthesia risks, presurgical and postsurgical complications, and in many cases a permanent state of hypoparathyroidism. Thus, the medical treatment of SHPT became an ideal target for the development of new therapies and strategies. The purpose of this article is to provide an overview of these new therapies, including vitamin D analogs, intestinal phosphate binders, calcimimetics, parathyroidectomies, tyrosine kinase inhibitors, azydothymidine, anticalcineurins, N-terminal truncated parathyroid hormone fragments, bisphosphonates, calcitonin, osteoprotegerin, and others. The use of these new therapies alone or in combination may help to optimize the future treatment of SHPT in CKD patients.
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Affiliation(s)
- Pablo Ureña Torres
- Service de Néphrologie et Dialyse, Clinique de l'Orangerie, Aubervilliers, France.
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Greenbaum LA, Del Rio M, Bamgbola F, Kaskel F. Rationale for growth hormone therapy in children with chronic kidney disease. Adv Chronic Kidney Dis 2004. [DOI: 10.1053/j.ackd.2004.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Disthabanchong S, Domrongkitchaiporn S, Sirikulchayanonta V, Stitchantrakul W, Karnsombut P, Rajatanavin R. Alteration of noncollagenous bone matrix proteins in distal renal tubular acidosis. Bone 2004; 35:604-13. [PMID: 15336595 DOI: 10.1016/j.bone.2004.04.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2003] [Revised: 04/01/2004] [Accepted: 04/30/2004] [Indexed: 11/15/2022]
Abstract
Our previous report on bone histomorphometry in patients with distal renal tubular acidosis (dRTA) revealed decreased bone formation rate (BFR) when compared to healthy subjects. The abnormality improved significantly after alkaline therapy. The modest increase in osteoblastic surface, after correction of metabolic acidosis, could not explain the striking improvement in bone formation, suggesting additional influence of metabolic acidosis on osteoblast function and/or bone matrix mineralization. Osteoblasts and, to a lesser extent, osteoclasts synthesize and secrete bone matrix including type I collagen and various noncollagenous proteins (NCPs). Substantial evidence suggested diverse functions of NCPs related to bone formation, resorption, and mineralization. Metabolic acidosis, through its effect on bone cells, may result in an alteration in the production of NCPs. Our study examined bone histomorphometry with detailed analysis on the mineralization parameters and NCPs expression within the bone matrix of patients with dRTA before and after treatment with alkaline. Seven dRTA patients underwent bone biopsy at their initial diagnosis and again 12 months after alkaline therapy. Bone mineral density (BMD) and bone histomorphometry were obtained at baseline and after the treatment. The expression of NCPs was examined by immunohistochemistry, quantitated by digital image analysis, and reported as a percentage of area of positive staining or mineralized trabecular bone area. Alkaline therapy normalized the low serum phosphate and PTH during acidosis. The reduction in BMD at baseline improved significantly by the treatment. Bone histomorphometry demonstrated the increase in osteoid surface and volume without significant alteration after acidosis correction. In comparison to the normal subjects, osteoid thickness was slightly but insignificantly elevated. Osteoblast and osteoclast populations and their activities were suppressed. The reduction in mineral apposition rate and adjusted apposition rate were observed in conjunction with the prolongation of mineralization lag time. Alkaline therapy improved the mineralization parameters considerably. In addition to the increase in BFR relative osteoblast number after acidosis correction, osteocalcin expression in the bone matrix increased significantly from 16.7% to 22.3%. Six of seven patients had decreased osteopontin expression. In conclusion, the abnormal bone remodeling in dRTA is characterized by low turnover bone disease with some degree of defective mineralization. Alteration of NCPs expression suggested the effect of metabolic acidosis on bone cells. Alkaline therapy increased bone mass through the restoration of bone mineral balance and, perhaps, improved osteoblast function.
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Affiliation(s)
- Sinee Disthabanchong
- Division of Nephrology, Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
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Green J, Goldberg R, Maor G. PTH ameliorates acidosis-induced adverse effects in skeletal growth centers: the PTH-IGF-I axis. Kidney Int 2003; 63:487-500. [PMID: 12631114 DOI: 10.1046/j.1523-1755.2003.00773.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Chronic metabolic acidosis (CMA) exerts profound adverse effects on bone metabolism thereby leading to impaired skeletal linear growth. We have recently shown that CMA in vitro causes distinct morphological changes in skeletal growth centers along with inhibition of endochondral differentiation. In addition, CMA causes an end organ resistance to the anabolic effects of growth hormone (GH) and locally produced insulin-like growth factor-I (IGF-I) in skeletal growth centers. Given the effects of parathyroid hormone (PTH) and PTH related protein (PTHrP) on the development of cartilaginous bone, we sought to determine whether PTH has any effects on the changes induced by CMA in skeletal growth centers. The interaction between PTH and IGF-I in growth centers during neutral or acidic conditions were studied specifically. METHODS An in vitro organ culture system using the murine mandibular condyle was employed as a model for endochondral active growth center. Condyles from six-day-old mice were cultured in BGJb medium of either neutral pH (pH approximately 7.4) or acidic pH (pH approximately 7.15) in the presence or absence of 10-10 mol/L [1-34] PTH. After 24, 48, 72 and 96 hours of culture, the condyles were washed, fixed in formaldehyde, and processed for paraffin embedding. Histologic markers of the growth center were assessed. In addition, the protein level and mRNA expression for various markers of cartilage differentiation were evaluated by immunohistochemistry and in situ hybridization, respectively. The abundance and expression levels of IGF-I and IGF-I receptor (IGF-I-R) were assessed also. RESULTS Following incubation for 72 hours in acidic conditions, there was a marked attenuation of the chondroblastic zone, suggesting a defect in the process of cellular differentiation. Acidosis also down-regulated endochondral differentiation markers (cartilage specific proteoglycans, collagen type II). This was accompanied by a reduction in the expression of IGF-1, IGF-1 receptor and PTH receptors. PTH (10-10 mol/L) added to acidic cultures prevented the adverse effects of CMA on endochondral differentiation and increased the overall condylar growth, when compared to acidic conditions without PTH. PTH also up-regulated its own receptor in control as well as during acidic conditions, and increased the expression levels of IGF-1 and IGF-1 receptor in the acidotic condyle. Acidosis increased the expression of IGF-I binding protein-4 (IGFBP-4, an inhibitor of IGF-I activity), whereas coincubation with PTH during acidic conditions abrogated the up-regulation of IGFBP-4. Addition of a neutralizing antibody to IGF-I-R during PTH treatment under acidic conditions resulted in the abrogation of the ameliorative effect of PTH on endochondral differentiation. The protein kinase C (PKC) signaling pathway was modulated negatively by CMA. However, PTH activated PKC-alpha under both control and acidic conditions. The phorbol ester, PMA (phorbol 12-myristate 13-acetate), a PKC activator, mimicked the effect of PTH on chondrocyte differentiation. CONCLUSION Parathyroid hormone at low concentration stimulates the differentiation and proliferation of cartilage cells and prevents the suppressive effect of acidosis on endochondral bone differentiation and on the IGF-I/IGF-I-R system in skeletal growth centers. Increased local production of IGF-I by PTH, which takes place even during acidotic conditions, mediates, at least in part, the ameliorative effect of PTH. Protein kinase C is probably one of the signaling pathways mediating the salutary effects of PTH on chondrocyte differentiation in growth centers. This study lends further credence to the notion that under certain conditions, PTH or PTHrP can exert anabolic effects in the skeleton. These findings may be of clinical-therapeutic significance in children and patients with CMA.
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Affiliation(s)
- Jacob Green
- Department of Nephrology, Rambam Medical Center, and the B. Rappaport Faculty of Medicine, Technion, Haifa, Israel
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Domrongkitchaiporn S, Pongskul C, Sirikulchayanonta V, Stitchantrakul W, Leeprasert V, Ongphiphadhanakul B, Radinahamed P, Rajatanavin R. Bone histology and bone mineral density after correction of acidosis in distal renal tubular acidosis. Kidney Int 2002; 62:2160-6. [PMID: 12427141 DOI: 10.1046/j.1523-1755.2002.00656.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The association between chronic metabolic acidosis and alterations in bone cell functions has been demonstrated in vitro and in animal studies. However, the causal role of acidosis and the effects of alkaline therapy on bone histology and bone mineral density in chronic metabolic acidosis have never been systematically demonstrated in humans. This study was conducted to examine the alterations in bone mineral density and bone histology before and after correction of acidosis among patients with distal renal tubular acidosis (dRTA) METHODS: Correction of metabolic acidosis by potassium citrate was done in non-azotemic dRTA patients, 6 females and 4 males, who had never received long-term alkaline therapy before enrolling into this study. Blood chemistries, serum intact parathyroid hormone, and 24-hour urine collection for the determination of urinary calcium, phosphate, sodium, potassium, bone mineral density determination, and transiliac bone biopsy were done in all patients at baseline and after one year of potassium citrate therapy. RESULTS Significant elevations in serum bicarbonate (16.5 +/- 3.0 vs. 24.6 +/- 2.8 mEq/L, P < 0.05) and urinary potassium excretion (35.2 +/- 7.9 vs. 55.4 +/-3.5 mEq/L, P < 0.05) were observed after potassium citrate therapy. No significant alterations in other serum and urine electrolytes were found after the therapy. Serum intact parathyroid hormone level was also significantly elevated after one year of treatment (12.8 +/- 7.3 vs. 26.2 +/- 8.7 pg/mL, P < 0.05). Bone formation rate was significantly suppressed at baseline and was normalized by the treatment (0.02 +/- 0.02 vs. 0.06 +/- 0.03 microm(3)/microm(2)/day, P < 0.05). There were non-significant elevations in trabecular bone volume, osteoblastic and osteoclastic numbers. Bone mineral densities in dRTA patients were also significantly decreased below normal values in most studied areas at baseline and were significantly elevated at the trochanter of femur (0.677 +/- 0.136 vs. 0.748 +/- 0.144 g/c m(2), P < 0.05) and total femur (0.898 +/- 0.166 vs. 0.976 +/- 0.154 g/c m(2), P < 0.05) after the treatment. CONCLUSIONS This study demonstrates that alkaline therapy corrects abnormal bone cell function and elevates bone mineral density in dRTA patients, indicating the causal role of acidosis in the alterations of bone cell functions and reduction in bone mineral density. Parathyroid gland activity also may be involved in the adaptation of the body to chronic metabolic acidosis.
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Affiliation(s)
- Somnuek Domrongkitchaiporn
- Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
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Reiter I, Tzukerman M, Maor G. Spontaneous differentiating primary chondrocytic tissue culture: a model for endochondral ossification. Bone 2002; 31:333-9. [PMID: 12151087 DOI: 10.1016/s8756-3282(02)00823-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Primary cartilage-derived cell cultures tend to undergo dedifferentiation, acquire fibroblastic features, and lose most of the characteristics of mature chondrocytes. This phenomenon is due mainly to the close matrix-cell interrelationship typical of cartilage tissue, which is vital for the preservation of the cartilaginous features. In this study we present a model for spontaneous redifferentiation of primary chondrocytic culture. Mandibular condyles excised from 3-day-old mice, thoroughly cleaned of all soft tissue, were digested with 0.1% collagenase. These mandibular condyle-derived chondrocytes (MCDC) were cultured under chondrogenesis-supporting conditions; that is, 5 x 10(5) cells/mL were incubated in Dulbecco's modified Eagle medium supplemented with 100 microg/mL ascorbic acid, 1 mmol/L calcium chloride, 10 mmol/L beta-glycerophosphate, 10% fetal calf serum, and antibiotics. Development and growth rates of these cartilage-derived cultures were determined by following morphological and functional changes. MCDC proliferated intensively during the first 24-48 h following plating, showing fibroblast-like (long spindle-shaped) morphology and producing mainly type I collagen. The proliferation rate gradually declined, and the cells developed polygonal shapes and started to produce type II collagen. In the 10-14-day-old cultures, cells began to aggregate in cartilaginous nodules and exhibited positive staining for acidic Alcian blue, type X collagen, and von Kossa. Expression of core-binding factor alpha(1) increased between 3 and 5 days and declined gradually thereafter. The condylar-derived tissue culture presented here depicts a spontaneous redifferentiation chondrocytic tissue culture that exhibits features of mature chondrocytes typically found in skeletal growth centers. The present study offers a model for primary chondrocytic tissue culture, which might serve as a model for in vitro endochondral ossification.
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Affiliation(s)
- I Reiter
- Department of Anatomy and Cell Biology, Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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Abstract
Type 1 diabetes generally results from autoimmune destruction of pancreatic islet beta-cells, with consequent absolute insulin deficiency and complete dependence on exogenous insulin treatment. The relative paucity of donations for pancreas or islet allograft transplantation has prompted the search for alternative sources for beta-cell replacement therapy. In the current study, we used pluripotent undifferentiated human embryonic stem (hES) cells as a model system for lineage-specific differentiation. Using hES cells in both adherent and suspension culture conditions, we observed spontaneous in vitro differentiation that included the generation of cells with characteristics of insulin-producing beta-cells. Immunohistochemical staining for insulin was observed in a surprisingly high percentage of cells. Secretion of insulin into the medium was observed in a differentiation-dependent manner and was associated with the appearance of other beta-cell markers. These findings validate the hES cell model system as a potential basis for enrichment of human beta-cells or their precursors, as a possible future source for cell replacement therapy in diabetes.
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Affiliation(s)
- S Assady
- Bruce Rappaport Faculty of Medicine, Technion, Israel Institute of Technology, and. Rambam Medical Center, Bat-Galim, Haifa, Israel
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Lemann J, Adams ND, Wilz DR, Brenes LG. Acid and mineral balances and bone in familial proximal renal tubular acidosis. Kidney Int 2000; 58:1267-77. [PMID: 10972690 DOI: 10.1046/j.1523-1755.2000.00282.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Metabolic acidosis caused by increased rates of fixed acid production is associated with increased urinary excretion of Ca and negative Ca balances. Metabolic acidosis caused by a reduced capacity of the kidneys to excrete acid contributes to the development of bone disease in the course of chronic renal failure and may be associated with bone disease among some patients with renal tubular acidosis. METHODS To assess the effects of life-long metabolic acidosis alone in the absence of other physiological disturbances, we measured the net balances of fixed acid and minerals in two brothers in a Costa Rican family with hereditary proximal renal tubular acidosis. Bone radiographs were assessed, and radial bone densities were measured. On a subsequent occasion, transiliac bone biopsies, following double-tetracycline labeling, were obtained from these two patients and an unaffected brother. RESULTS During the balance studies, serum [HCO3-] concentrations of the two affected patients were stable at 12.5 +/- 0.9 and 19.2 +/- 0.7 mmol/L, respectively. Their rates of net fixed acid production were normal and appropriate for their body weights, averaging 0.90 and 1.02 mEq/kg/day. Because their distal renal tubular function was normal, they were capable of acidifying their urine maximally, allowing sufficient urinary excretion of titratable acid and ammonium to maintain net acid excretion at a level that matched acid production. Thus, their acid balances were near zero, as observed among healthy subjects, at -1.9 +/- 2.3 and -2.2 +/- 2.2 mEq/day, respectively. Their rates of urinary Ca excretion were normal at 1.6 +/- 0.3 and 2.7 +/- 2.4 mmol/day, and the their balances of Ca and other minerals were close to zero so that ongoing bone loss was not occurring despite the acidosis. Nevertheless, their heights, relative to their ages, were shorter than the heights of their unaffected relatives. Their radial bone densities were lower than normal for their age and sex, and their iliac cortices were thinner than that of their unaffected brother. However, they had no histomorphometric evidence of osteomalacia or osteitis fibrosa, and their rates of bone mineralization were normal. CONCLUSIONS The results indicate that this chronic metabolic acidosis reduces growth, including that of bone. We speculate, without direct supporting evidence, that bone stores of HCO3-/CO3= are reduced, as has been observed in patients with the metabolic acidosis of chronic renal failure and in experimental metabolic acidosis in animals.
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Affiliation(s)
- J Lemann
- Nephrology Division, Department of Medicine and Clinical Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
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