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Healthy and Chronic Kidney Disease (CKD) Dogs Have Differences in Serum Metabolomics and Renal Diet May Have Slowed Disease Progression. Metabolites 2021; 11:metabo11110782. [PMID: 34822440 PMCID: PMC8623449 DOI: 10.3390/metabo11110782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 10/28/2021] [Accepted: 11/03/2021] [Indexed: 11/17/2022] Open
Abstract
Chronic kidney disease (CKD) is highly prevalent in dogs, and metabolomics investigation has been recently introduced for a better understanding of the role of diet in CKD. This study aimed to compare the serum metabolomic profile of healthy dogs (CG) and dogs with CKD (CKD-T0 and CKD-T6) to evaluate whether the diet would affect metabolites. Six dogs (5 females; 1 male; 7.47 ± 2.31 years old) with CKD stage 3 or 4 (IRIS) were included. CG consisted of 10 healthy female dogs (5.89 ± 2.57 years old) fed a maintenance diet. Serum metabolites were analyzed by 1H nuclear magnetic resonance (1H NMR) spectra. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were performed to assess differences in metabolomic profiles between groups and before (CKD-T0) and after renal diet (CKD-T6). Data analysis was performed on SIMCA-P software. Dogs with CKD showed an altered metabolic profile with increased urea, creatinine, creatine, citrate, and lipids. Lactate, branched-chain amino acids (BCAAs), and glutamine were decreased in the CKD group. However, after 6 months of diet, the metabolite profiles of CKD-T0 and CKD-T6 were similar. Metabolomics profile may be useful to evaluate and recognize metabolic dysfunction and progression of CKD, and the diet may have helped maintain and retard the progression of CKD.
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Velasquez MT, Centron P, Barrows I, Dwivedi R, Raj DS. Gut Microbiota and Cardiovascular Uremic Toxicities. Toxins (Basel) 2018; 10:E287. [PMID: 29997362 PMCID: PMC6071268 DOI: 10.3390/toxins10070287] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/05/2018] [Accepted: 07/06/2018] [Indexed: 02/07/2023] Open
Abstract
Cardiovascular disease (CVD) remains a major cause of high morbidity and mortality in patients with chronic kidney disease (CKD). Numerous CVD risk factors in CKD patients have been described, but these do not fully explain the high pervasiveness of CVD or increased mortality rates in CKD patients. In CKD the loss of urinary excretory function results in the retention of various substances referred to as "uremic retention solutes". Many of these molecules have been found to exert toxicity on virtually all organ systems of the human body, leading to the clinical syndrome of uremia. In recent years, an increasing body of evidence has been accumulated that suggests that uremic toxins may contribute to an increased cardiovascular disease (CVD) burden associated with CKD. This review examined the evidence from several clinical and experimental studies showing an association between uremic toxins and CVD. Special emphasis is addressed on emerging data linking gut microbiota with the production of uremic toxins and the development of CKD and CVD. The biological toxicity of some uremic toxins on the myocardium and the vasculature and their possible contribution to cardiovascular injury in uremia are also discussed. Finally, various therapeutic interventions that have been applied to effectively reduce uremic toxins in patients with CKD, including dietary modifications, use of prebiotics and/or probiotics, an oral intestinal sorbent that adsorbs uremic toxins and precursors, and innovative dialysis therapies targeting the protein-bound uremic toxins are also highlighted. Future studies are needed to determine whether these novel therapies to reduce or remove uremic toxins will reduce CVD and related cardiovascular events in the long-term in patients with chronic renal failure.
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Affiliation(s)
- Manuel T Velasquez
- Division of Renal Diseases and Hypertension, The George Washington University, Washington, DC 20037, USA.
| | - Patricia Centron
- Division of Renal Diseases and Hypertension, The George Washington University, Washington, DC 20037, USA.
| | - Ian Barrows
- Department of Medicine, Georgetown University, Washington, DC 20007, USA.
| | - Rama Dwivedi
- Division of Renal Diseases and Hypertension, The George Washington University, Washington, DC 20037, USA.
- United States Food and Drug Administration, Silver Spring, MD 20993, USA.
| | - Dominic S Raj
- Division of Renal Diseases and Hypertension, The George Washington University, Washington, DC 20037, USA.
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Abstract
Chronic kidney disease (CKD) has a prevalence of approximately 13% and is most frequently caused by diabetes and hypertension. In population studies, CKD etiology is often uncertain. Some experimental and observational human studies have suggested that high-protein intake may increase CKD progression and even cause CKD in healthy people. The protein source may be important. Daily red meat consumption over years may increase CKD risk, whereas white meat and dairy proteins appear to have no such effect, and fruit and vegetable proteins may be renal protective. Few randomized trials exist with an observation time greater than 6 months, and most of these were conducted in patients with preexisting diseases that dispose to CKD. Results conflict and do not allow any conclusion about kidney-damaging effects of long-term, high-protein intake. Until additional data become available, present knowledge seems to substantiate a concern. Screening for CKD should be considered before and during long-term, high-protein intake.
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Affiliation(s)
- Anne-Lise Kamper
- Department of Nephrology, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark;
| | - Svend Strandgaard
- Department of Nephrology, Herlev Hospital, University of Copenhagen, 2730 Copenhagen, Denmark;
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Chauveau P, Moreau K, Lasseur C, Combe C, Aparicio M. [Common therapeutic approaches of sarcopenia in the elderly and uremic myopathy]. Nephrol Ther 2017; 13:511-517. [PMID: 28606408 DOI: 10.1016/j.nephro.2016.12.004] [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: 08/08/2016] [Revised: 12/04/2016] [Accepted: 12/11/2016] [Indexed: 10/19/2022]
Abstract
The gradual loss of weight and function of muscle in patients with chronic kidney disease as in the elderly impacts the quality of life. Early management should help slow the functional limitation. Physical activity is the first therapy to propose that ensures stability of muscle mass and improved function. Resistance training programs have proven effective but are not yet widely available in nephrology units. The nutritional management should not be forgotten because there is a resistance to anabolism and protein intake should be involved in physical activity program. Associated treatments should not be neglected: vitamin D, anti-inflammatory, androgens. Some are still under evaluation. Therapeutic option, tomorrow, could be anti-myostatin antibodies and glitazones.
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Affiliation(s)
- Philippe Chauveau
- Service de néphrologie transplantation dialyse, hôpital Pellegrin, CHU de Bordeaux, place Amélie-Raba-Léon, 33000 Bordeaux, France; Aurad-Aquitaine, 2, allée des Demoiselles, 33170 Gradignan, France.
| | - Karine Moreau
- Service de néphrologie transplantation dialyse, hôpital Pellegrin, CHU de Bordeaux, place Amélie-Raba-Léon, 33000 Bordeaux, France
| | - Catherine Lasseur
- Service de néphrologie transplantation dialyse, hôpital Pellegrin, CHU de Bordeaux, place Amélie-Raba-Léon, 33000 Bordeaux, France; Aurad-Aquitaine, 2, allée des Demoiselles, 33170 Gradignan, France
| | - Christian Combe
- Service de néphrologie transplantation dialyse, hôpital Pellegrin, CHU de Bordeaux, place Amélie-Raba-Léon, 33000 Bordeaux, France; Unité INSERM 1026, Univ. Bordeaux, Bordeaux, France
| | - Michel Aparicio
- Service de néphrologie transplantation dialyse, hôpital Pellegrin, CHU de Bordeaux, place Amélie-Raba-Léon, 33000 Bordeaux, France
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Lee HW, Osis G, Handlogten ME, Verlander JW, Weiner ID. Proximal tubule glutamine synthetase expression is necessary for the normal response to dietary protein restriction. Am J Physiol Renal Physiol 2017; 313:F116-F125. [PMID: 28331060 DOI: 10.1152/ajprenal.00048.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/15/2017] [Accepted: 03/20/2017] [Indexed: 01/15/2023] Open
Abstract
Dietary protein restriction has multiple benefits in kidney disease. Because protein intake is a major determinant of endogenous acid production, it is important that net acid excretion changes in parallel during changes in dietary protein intake. Dietary protein restriction decreases endogenous acid production and decreases urinary ammonia excretion, a major component of net acid excretion. Glutamine synthetase (GS) catalyzes the reaction of [Formula: see text] and glutamate, which regenerates the essential amino acid glutamine and decreases net ammonia generation. Because renal proximal tubule GS expression increases during dietary protein restriction, this could contribute to the decreased ammonia excretion. The purpose of the current study was to determine the role of proximal tubule GS in the renal response to protein restriction. We generated mice with proximal tubule-specific GS deletion (PT-GS-KO) using Cre-loxP techniques. Cre-negative (Control) and PT-GS-KO mice in metabolic cages were provided 20% protein diet for 2 days and were then changed to low-protein (6%) diet for the next 7 days. Additional PT-GS-KO mice were maintained on 20% protein diet. Dietary protein restriction caused a rapid decrease in urinary ammonia excretion in both genotypes, but PT-GS-KO blunted this adaptive response significantly. This occurred despite no significant genotype-dependent differences in urinary pH or in serum electrolytes. There were no significant differences between Control and PT-GS-KO mice in expression of multiple other proteins involved in renal ammonia handling. We conclude that proximal tubule GS expression is necessary for the appropriate decrease in ammonia excretion during dietary protein restriction.
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Affiliation(s)
- Hyun-Wook Lee
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida; and
| | - Gunars Osis
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida; and
| | - Mary E Handlogten
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida; and
| | - Jill W Verlander
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida; and
| | - I David Weiner
- Division of Nephrology, Hypertension and 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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Maxia S, Loi V, Capizzi I, Piccoli GB, Cabiddu G, Pani A. Compliance, illiteracy and low-protein diet: multiple challenges in CKD and a case of self-empowerment. BMC Nephrol 2016; 17:138. [PMID: 27683011 PMCID: PMC5041291 DOI: 10.1186/s12882-016-0353-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 09/22/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Low-protein diets (LPD) are an important means of delaying the need for dialysis and attaining a stable metabolic balance in chronic kidney disease (CKD). Many authors consider a low educational level and illiteracy to be adverse features for a good dietary compliance. CASE PRESENTATION We report the case of a 77-year old woman, illiterate, affected by advanced CKD (stage 4 according to KDIGO guidelines). She was initially ashamed of her problem and did not declare it, leading to an overzealous reduction in protein intake. However, with her daughter's help, who translated the dietary prescription into images, she overcame the barrier represented by illiteracy and was able to correctly follow the prescriptions, attaining good kidney function stability and preserving an adequate nutritional status. CONCLUSIONS The case underlines the importance of a personalized approach to dietary prescriptions and suggests that it is possible to achieve a good compliance to the dietary treatment of CKD also in patients with relevant cultural barriers.
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Affiliation(s)
- Stefania Maxia
- SC Nephrology and Dialysis, Brotzu Hospital, Piazzale Alessandro Ricchi 1, 09134, Cagliari, Italy
| | - Valentina Loi
- SC Nephrology and Dialysis, Brotzu Hospital, Piazzale Alessandro Ricchi 1, 09134, Cagliari, Italy
| | - Irene Capizzi
- SS Nephrology, SCDU Urologia, Department of Clinical and Biological Sciences, University of Torino, San Luigi Gonzaga Hospital, Regione Gonzole 10, 10043, Orbassano, Italy
| | - Giorgina Barbara Piccoli
- SS Nephrology, SCDU Urologia, Department of Clinical and Biological Sciences, University of Torino, San Luigi Gonzaga Hospital, Regione Gonzole 10, 10043, Orbassano, Italy.,Nephrologie, Centre Hospitalier Le Mans, 194 av. Rubillard, 72037, Le Mans, France
| | - Gianfranca Cabiddu
- SC Nephrology and Dialysis, Brotzu Hospital, Piazzale Alessandro Ricchi 1, 09134, Cagliari, Italy.
| | - Antonello Pani
- SC Nephrology and Dialysis, Brotzu Hospital, Piazzale Alessandro Ricchi 1, 09134, Cagliari, Italy
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Recent advances in the pathophysiology and management of protein-energy wasting in chronic kidney disease. RENAL REPLACEMENT THERAPY 2016. [DOI: 10.1186/s41100-016-0015-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Weiner ID, Mitch WE, Sands JM. Urea and Ammonia Metabolism and the Control of Renal Nitrogen Excretion. Clin J Am Soc Nephrol 2015; 10:1444-58. [PMID: 25078422 PMCID: PMC4527031 DOI: 10.2215/cjn.10311013] [Citation(s) in RCA: 237] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Renal nitrogen metabolism primarily involves urea and ammonia metabolism, and is essential to normal health. Urea is the largest circulating pool of nitrogen, excluding nitrogen in circulating proteins, and its production changes in parallel to the degradation of dietary and endogenous proteins. In addition to serving as a way to excrete nitrogen, urea transport, mediated through specific urea transport proteins, mediates a central role in the urine concentrating mechanism. Renal ammonia excretion, although often considered only in the context of acid-base homeostasis, accounts for approximately 10% of total renal nitrogen excretion under basal conditions, but can increase substantially in a variety of clinical conditions. Because renal ammonia metabolism requires intrarenal ammoniagenesis from glutamine, changes in factors regulating renal ammonia metabolism can have important effects on glutamine in addition to nitrogen balance. This review covers aspects of protein metabolism and the control of the two major molecules involved in renal nitrogen excretion: urea and ammonia. Both urea and ammonia transport can be altered by glucocorticoids and hypokalemia, two conditions that also affect protein metabolism. Clinical conditions associated with altered urine concentrating ability or water homeostasis can result in changes in urea excretion and urea transporters. Clinical conditions associated with altered ammonia excretion can have important effects on nitrogen balance.
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Affiliation(s)
- I David Weiner
- Nephrology and Hypertension Section, North Florida/South Georgia Veterans Health System, Gainesville, Florida; Division of Nephrology, Hypertension, and Transplantation, University of Florida College of Medicine, Gainesville, Florida;
| | - William E Mitch
- Nephrology Division, Baylor College of Medicine, Houston, Texas; and
| | - Jeff M Sands
- Nephrology Division, Emory University School of Medicine, Atlanta, Georgia
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Lee HW, Osis G, Handlogten ME, Guo H, Verlander JW, Weiner ID. Effect of dietary protein restriction on renal ammonia metabolism. Am J Physiol Renal Physiol 2015; 308:F1463-73. [PMID: 25925252 DOI: 10.1152/ajprenal.00077.2015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 04/20/2015] [Indexed: 11/22/2022] Open
Abstract
Dietary protein restriction has multiple benefits in kidney disease. Because protein intake is a major determinant of endogenous acid production, it is important that net acid excretion change in parallel during protein restriction. Ammonia is the primary component of net acid excretion, and inappropriate ammonia excretion can lead to negative nitrogen balance. Accordingly, we examined ammonia excretion in response to protein restriction and then we determined the molecular mechanism of the changes observed. Wild-type C57Bl/6 mice fed a 20% protein diet and then changed to 6% protein developed an 85% reduction in ammonia excretion within 2 days, which persisted during a 10-day study. The expression of multiple proteins involved in renal ammonia metabolism was altered, including the ammonia-generating enzymes phosphate-dependent glutaminase (PDG) and phosphoenolpyruvate carboxykinase (PEPCK) and the ammonia-metabolizing enzyme glutamine synthetase. Rhbg, an ammonia transporter, increased in expression in the inner stripe of outer medullary collecting duct intercalated cell (OMCDis-IC). However, collecting duct-specific Rhbg deletion did not alter the response to protein restriction. Rhcg deletion did not alter ammonia excretion in response to dietary protein restriction. These results indicate 1) dietary protein restriction decreases renal ammonia excretion through coordinated regulation of multiple components of ammonia metabolism; 2) increased Rhbg expression in the OMCDis-IC may indicate a biological role in addition to ammonia transport; and 3) Rhcg expression is not necessary to decrease ammonia excretion during dietary protein restriction.
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Affiliation(s)
- Hyun-Wook Lee
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Gunars Osis
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Mary E Handlogten
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Hui Guo
- Division of Nephrology, Second Hospital of Shanxi Medical University, Yaiyuan, Shanxi, Peoples Republic of China; and
| | - 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, Medical Service, North Florida/South Georgia Veterans Health System, Gainesville, Florida
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Abstract
Chaperone-mediated autophagy (CMA) is a lysosomal proteolytic pathway in which cytosolic substrate proteins contain specific chaperone recognition sequences required for degradation and are translocated directly across the lysosomal membrane for destruction. CMA proteolytic activity has a reciprocal relationship with macroautophagy: CMA is most active in cells in which macroautophagy is least active. Normal renal proximal tubular cells have low levels of macroautophagy, but high basal levels of CMA activity. CMA activity is regulated by starvation, growth factors, oxidative stress, lipids, aging, and retinoic acid signaling. The physiological consequences of changes in CMA activity depend on the substrate proteins present in a given cell type. In the proximal tubule, increased CMA results from protein or calorie starvation and from oxidative stress. Overactivity of CMA can be associated with tubular lysosomal pathology and certain cancers. Reduced CMA activity contributes to protein accumulation in renal tubular hypertrophy, but may contribute to oxidative tissue damage in diabetes and aging. Although there are more questions than answers about the role of high basal CMA activity, this remarkable feature of tubular protein metabolism appears to influence a variety of chronic diseases.
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Affiliation(s)
- Harold A Franch
- Research Service, Atlanta Veterans Affairs Medical Center, Decatur, GA; and Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, GA.
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Rice protein ameliorates the progression of diabetic nephropathy in Goto–Kakizaki rats with high-sucrose feeding. Br J Nutr 2013; 110:1211-9. [DOI: 10.1017/s0007114513000354] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The effect of rice protein (RP) on diabetic nephropathy in non-obese, spontaneous type 2 diabetic Goto–Kakizaki (GK) rats was investigated. GK rats at 7 weeks of age were fed 20 % RP or casein (C) in standard or high-sucrose diets for 10 weeks. Plasma total cholesterol, TAG, alkaline phosphatase (ALP), adiponectin, creatinine and urinary albumin excretion (UAE) were measured and renal histology was evaluated. Compared with C, RP lowered plasma TAG and improved plasma adiponectin levels in GK rats fed the standard diet (P< 0·05), and also lowered total cholesterol and ALP in high-sucrose-fed GK rats (P< 0·05). RP markedly suppressed the sharp increase in UAE when GK rats were fed high-sucrose diets (P< 0·05), and prevented glomerular mesangial matrix expansion in the deep renal cortex near the corticomedullary junction (P< 0·05). These results strongly indicate that dietary RP can ameliorate the progression of diabetic nephropathy at an early stage compared with C.
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Carrero JJ, Stenvinkel P, Cuppari L, Ikizler TA, Kalantar-Zadeh K, Kaysen G, Mitch WE, Price SR, Wanner C, Wang AY, ter Wee P, Franch HA. Etiology of the Protein-Energy Wasting Syndrome in Chronic Kidney Disease: A Consensus Statement From the International Society of Renal Nutrition and Metabolism (ISRNM). J Ren Nutr 2013; 23:77-90. [DOI: 10.1053/j.jrn.2013.01.001] [Citation(s) in RCA: 458] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 01/15/2013] [Indexed: 01/17/2023] Open
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Lacson E, Wang W, Zebrowski B, Wingard R, Hakim RM. Outcomes associated with intradialytic oral nutritional supplements in patients undergoing maintenance hemodialysis: a quality improvement report. Am J Kidney Dis 2012; 60:591-600. [PMID: 22632807 DOI: 10.1053/j.ajkd.2012.04.019] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 04/24/2012] [Indexed: 02/02/2023]
Abstract
BACKGROUND Insufficient clinical data exist to determine whether provision of oral nutritional supplements during dialysis can improve survival in hypoalbuminemic maintenance hemodialysis patients. STUDY DESIGN Retrospective matched-cohort study. SETTING & PARTICIPANTS All oral nutritional supplement program-eligible in-center maintenance hemodialysis patients with albumin level ≤3.5 g/dL in quarter 4 of 2009 without oral nutritional supplements in the prior 90 days at Fresenius Medical Care, North America facilities. QUALITY IMPROVEMENT PLAN Monitored intradialytic oral nutritional supplements were provided to eligible maintenance hemodialysis patients upon physician order, to continue for a year or until serum albumin level was ≥4.0 g/dL. OUTCOME Mortality (including deaths and withdrawals), followed up until December 31, 2010. MEASUREMENTS Both an intention-to-treat (ITT) and an as-treated analysis was performed using a 1:1 geographic region and propensity score-matched study population (using case-mix, laboratory test, access type, 30-day prior hospitalization, and incident patient status) comparing patients treated with intradialytic oral nutritional supplements with usual-care patients. Cox models were constructed, unadjusted and adjusted for facility standardized mortality ratio and case-mix and laboratory variables. RESULTS The ITT and as-treated analyses both showed lower mortality in the oral nutritional supplement group. The conservative ITT models with 5,227 matched pairs had 40% of controls subsequently receiving oral nutritional supplements after January 1, 2010 (because many physicians delayed participation), with comparative death rates of 30.1% versus 30.4%. The corresponding as-treated (excluding crossovers) death rates for 4,289 matched pairs were 30.9% versus 37.3%. The unadjusted ITT mortality HR for oral nutritional supplement use was 0.95 (95% CI, 0.88-1.01), and the adjusted HR was 0.91 (95% CI, 0.85-0.98); the corresponding as-treated HRs were 0.71 (95% CI, 0.66-0.76) and 0.66 (95% CI, 0.61-0.71) before and after adjustment, respectively. LIMITATIONS Limited capture of oral nutritional supplement intake outside the facility and potential residual confounding from unmeasured variables, such as dietary intake. CONCLUSIONS Maintenance hemodialysis patients with albumin levels ≤3.5 g/dL who received monitored intradialytic oral nutritional supplements showed survival significantly better than similar matched patient controls, with the as-treated analysis highlighting the potentially large effect of this strategy in clinical practice.
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Affiliation(s)
- Eduardo Lacson
- Fresenius Medical Care, North America, Waltham, MA, USA.
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14
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Chung S, Koh ES, Shin SJ, Park CW. Malnutrition in patients with chronic kidney disease. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/ojim.2012.22018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Chen Y, Sood S, McIntire K, Roth R, Rabkin R. Leucine-stimulated mTOR signaling is partly attenuated in skeletal muscle of chronically uremic rats. Am J Physiol Endocrinol Metab 2011; 301:E873-81. [PMID: 21791619 DOI: 10.1152/ajpendo.00068.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The branched-chain amino acid leucine stimulates muscle protein synthesis in part by directly activating the mTOR signaling pathway. Furthermore, leucine, if given in conjunction with resistance exercise, enhances the exercise-induced mTOR signaling and protein synthesis. Here we tested whether leucine can activate the mTOR anabolic signaling pathway in uremia and whether it can enhance work overload (WO)-induced signaling through this pathway. Chronic kidney disease (CKD) and control rats were studied after 7 days of surgically induced unilateral plantaris muscle WO and a single leucine or saline load. In the basal state, 4E-BP1 phosphorylation was modestly depressed in non-WO muscle of CKD rats, whereas rpS6 phosphorylation was nearly completely suppressed. After oral leucine mTOR, S6K1 and rpS6 phosphorylation increased similarly in both groups, whereas the phospho-4E-BP1 response was modestly attenuated in CKD. WO alone activated the mTOR signaling pathway in control and CKD rats. In WO CKD, muscle leucine augmented mTOR and 4E-BP1 phosphorylation, but its effect on S6K1 phosphorylation was attenuated. Taken together, this study has established that the chronic uremic state impairs basal signaling through the mTOR anabolic pathway, an abnormality that may contribute to muscle wasting. However, despite this abnormality, leucine can stimulate this signaling pathway in CKD, although its effectiveness is partially attenuated, including in skeletal muscle undergoing sustained WO. Thus, although there is some resistance to leucine in CKD, the data suggest a potential role for leucine-rich supplements in the management of uremic muscle wasting.
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Affiliation(s)
- Yu Chen
- Research Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304, USA
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Garibotto G, Sofia A, Saffioti S, Bonanni A, Mannucci I, Verzola D. Amino acid and protein metabolism in the human kidney and in patients with chronic kidney disease. Clin Nutr 2010; 29:424-33. [PMID: 20207454 DOI: 10.1016/j.clnu.2010.02.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 02/06/2010] [Accepted: 02/09/2010] [Indexed: 11/26/2022]
Abstract
The progressive loss of kidney function in patients with chronic kidney disease (CKD) is associated with a number of complications, including cardiovascular diseases, anemia, hyperparathyroidism, inflammation, metabolic acidosis, malnutrition and protein-energy wasting. The excess cardiovascular risk related to CKD is due in part to a higher prevalence of traditional atherosclerotic risk factors, in part to non-traditional, emerging risk factors peculiar to CKD. While even minor renal dysfunction is an independent predictor of adverse cardiovascular prognosis, nutritional changes are more often observed in an advanced setting. In addition, factors related to renal-replacement treatment may be implicated in the pathogenesis of heart disease and protein-energy wasting in dialysis-treated patients. Progressive alterations in kidney metabolism may cause progressive effects on cardiovascular status and nutrition. Altered kidney amino acid/protein metabolism and or excretion may be a key factor in the homeostasis of several vasoactive compounds and hormones in patients with more advanced disease. In this discussion recent research regarding the kidney handling of amino acids and protein turnover and their potential link with cardiovascular disease, progressive kidney dysfunction and nutritional status are reviewed.
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