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Journal of Nephrology Dec 2021Renal tubular acidosis (RTA) comprises a group of disorders in which excretion of hydrogen ions or reabsorption of filtered HCO is impaired, leading to chronic metabolic... (Review)
Review
Renal tubular acidosis (RTA) comprises a group of disorders in which excretion of hydrogen ions or reabsorption of filtered HCO is impaired, leading to chronic metabolic acidosis with normal anion gap. In the current review, the focus is placed on the most common type of RTA, Type 1 RTA or Distal RTA (dRTA), which is a rare chronic genetic disorder characterized by an inability of the distal nephron to secrete hydrogen ions in the presence of metabolic acidosis. Over the years, knowledge of the molecular mechanisms behind acid secretion has improved, thereby greatly helping the diagnosis of dRTA. The primary or inherited form of dRTA is mostly diagnosed in infancy, childhood, or young adulthood, while the acquired secondary form, as a consequence of other disorders or medications, can happen at any age, although it is more commonly seen in adults. dRTA is not as "benign" as previously assumed, and can have several, highly variable long-term consequences. The present review indeed reports and summarizes both clinical symptoms and diagnosis, long-term outcomes, genetic inheritance, epidemiology and current treatment options, with the aim of shedding more light onto this rare disorder. Being a chronic condition, dRTA also deserves attention in the transition between pediatric and adult nephrology care, and as a rare disease it has a place in the European and Italian rare nephrological diseases network.
Topics: Acid-Base Equilibrium; Acidosis, Renal Tubular; Adult; Biological Transport; Child; Humans; Young Adult
PubMed: 33770395
DOI: 10.1007/s40620-021-01032-y -
BioMed Research International 2020Two enantiomers of lactic acid exist. While L-lactic acid is a common compound of human metabolism, D-lactic acid is produced by some strains of microorganism or by some... (Review)
Review
Two enantiomers of lactic acid exist. While L-lactic acid is a common compound of human metabolism, D-lactic acid is produced by some strains of microorganism or by some less relevant metabolic pathways. While L-lactic acid is an endogenous compound, D-lactic acid is a harmful enantiomer. Exposure to D-lactic acid can happen by various ways including contaminated food and beverages and by microbiota during some pathological states like short bowel syndrome. The exposure to D-lactic acid cannot be diagnosed because the common analytical methods are not suitable for distinguishing between the two enantiomers. In this review, pathways for D-lactic acid, pathological processes, and diagnostical and analytical methods are introduced followed by figures and tables. The current literature is summarized and discussed.
Topics: Acidosis; Animals; Humans; Lactic Acid; Metabolic Networks and Pathways; Metabolome
PubMed: 32685468
DOI: 10.1155/2020/3419034 -
Journal of the American Society of... Feb 2021The kidney plays an important role in maintaining normal blood pH. Metabolic acidosis (MA) upregulates the pathway that mitochondria in the proximal tubule (PT) use to...
BACKGROUND
The kidney plays an important role in maintaining normal blood pH. Metabolic acidosis (MA) upregulates the pathway that mitochondria in the proximal tubule (PT) use to produce ammonia and bicarbonate from glutamine, and is associated with AKI. However, the extent to which MA causes AKI, and thus whether treating MA would be beneficial, is unclear.
METHODS
Gavage with ammonium chloride induced acute MA. Multiphoton imaging of mitochondria (NADH/membrane potential) and transport function (dextran/albumin uptake), oxygen consumption rate (OCR) measurements in isolated tubules, histologic analysis, and electron microscopy in fixed tissue, and urinary biomarkers (KIM-1/clara cell 16) assessed tubular cell structure and function in mouse kidney cortex.
RESULTS
MA induces an acute change in NAD redox state (toward oxidation) in PT mitochondria, without changing the mitochondrial energization state. This change is associated with a switch toward complex I activity and decreased maximal OCR, and a major alteration in normal lipid metabolism, resulting in marked lipid accumulation in PTs and the formation of large multilamellar bodies. These changes, in turn, lead to acute tubular damage and a severe defect in solute uptake. Increasing blood pH with intravenous bicarbonate substantially improves tubular function, whereas preinjection with the NAD precursor nicotinamide (NAM) is highly protective.
CONCLUSIONS
MA induces AKI changes in PT NAD and lipid metabolism, which can be reversed or prevented by treatment strategies that are viable in humans. These findings might also help to explain why MA accelerates decline in function in CKD.
Topics: Acidosis; Acute Kidney Injury; Animals; Disease Models, Animal; Kidney Cortex; Kidney Tubules; Lipid Metabolism; Male; Mice; Mice, Inbred C57BL; Mitochondria; NAD; Oxygen Consumption
PubMed: 33478973
DOI: 10.1681/ASN.2020071003 -
Journal of Nephrology Dec 2019Metabolic acidosis is associated with accelerated progression of chronic kidney disease (CKD). Whether treatment of metabolic acidosis with sodium bicarbonate improves... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Metabolic acidosis is associated with accelerated progression of chronic kidney disease (CKD). Whether treatment of metabolic acidosis with sodium bicarbonate improves kidney and patient survival in CKD is unclear.
METHODS
We conducted a randomized (ratio 1:1). open-label, controlled trial (NCT number: NCT01640119. www.clinicaltrials.gov ) to determine the effect in patients with CKD stage 3-5 of treatment of metabolic acidosis with sodium bicarbonate (SB) on creatinine doubling (primary endpoint), all-cause mortality and time to renal replacement therapy compared to standard care (SC) over 36-months. Parametric, non-parametric tests and survival analyses were used to assess the effect of SB on these outcomes.
RESULTS
A total of 376 and 364 individuals with mean (SD) age 67.8 (14.9) years, creatinine clearance 30 (12) ml/min, and serum bicarbonate 21.5 (2.4) mmol/l were enrolled in SB and SC, respectively. Mean (SD) follow-up was 29.6 (9.8) vs 30.3 (10.7) months in SC and SB. respectively. The mean (SD) daily doses of SB was 1.13 (0.10). 1.12 (0.11). and 1.09 (0.12) mmol/kg*bw/day in the first, second and third year of follow-up, respectively. A total of 87 participants reached the primary endpoint [62 (17.0%) in SC vs 25 (6.6%) in SB, p < 0.001). Similarly, 71 participants [45 (12.3%) in SC and 26 (6.9%) in SB, p = 0.016] started dialysis while 37 participants [25 (6.8%) in SC and 12 (3.1%) in SB, p = 0.004] died. There were no significant effect of SB on blood pressure, total body weight or hospitalizations.
CONCLUSION
In persons with CKD 3-5 without advanced stages of chronic heart failure, treatment of metabolic acidosis with sodium bicarbonate is safe and improves kidney and patient survival.
Topics: Acidosis; Aged; Disease Progression; Female; Glomerular Filtration Rate; Humans; Italy; Kidney; Male; Renal Insufficiency, Chronic; Sodium Bicarbonate; Survival Rate
PubMed: 31598912
DOI: 10.1007/s40620-019-00656-5 -
Ugeskrift For Laeger Aug 2021It is a common but flawed presumption that blood lactate reflects the lactic acid production in the body's tissues. Lactate is formed directly from pyruvate and... (Review)
Review
It is a common but flawed presumption that blood lactate reflects the lactic acid production in the body's tissues. Lactate is formed directly from pyruvate and functions to dampen reductions in intracellular pH through lactate-H+ cotransport to the extracellular space. Though this may give rise to elevated blood lactate, increased lactate production is not the cause of metabolic acidosis in such instances. "Lactic acidosis" is thus an inappropriate term as it indicates causality and in this review, we suggest that in the future, the term "hyperlactataemia-associated metabolic acidosis" should be used instead.
Topics: Acidosis; Acidosis, Lactic; Humans; Lactic Acid
PubMed: 34477100
DOI: No ID Found -
Nutrients Feb 2023Dietary protein restriction has long been a cornerstone of nutritional therapy for patients with chronic kidney diseases (CKD). However, the recommended amount of... (Review)
Review
Dietary protein restriction has long been a cornerstone of nutritional therapy for patients with chronic kidney diseases (CKD). However, the recommended amount of dietary protein intake is different across guidelines. This is partly because previous randomized controlled trials have reported conflicting results regarding the efficacy of protein restriction in terms of kidney outcomes. Interestingly, a vegetarian, very low protein diet has been shown to reduce the risk of kidney failure among patients with advanced CKD, without increasing the incidence of hyperkalemia. This finding suggests that the source of protein may also influence the kidney outcomes. Furthermore, a plant-dominant low-protein diet (PLADO) has recently been proposed as an alternative dietary therapy for patients with CKD. There are several potential mechanisms by which plant-based diets would benefit patients with CKD. For example, plant-based diets may reduce the production of gut-derived uremic toxins by increasing the intake of fiber, and are useful for correcting metabolic acidosis and hyperphosphatemia. Plant proteins are less likely to induce glomerular hyperfiltration than animal proteins. Furthermore, plant-based diets increase magnesium intake, which may prevent vascular calcification. More evidence is needed to establish the efficacy, safety, and feasibility of PLADO as a new adjunct therapy in real-world patients with CKD.
Topics: Animals; Diet, Protein-Restricted; Dietary Proteins; Renal Insufficiency, Chronic; Kidney; Acidosis
PubMed: 36839360
DOI: 10.3390/nu15041002 -
Clinical Journal of the American... Aug 2021Acid-related injury from chronic metabolic acidosis is recognized through growing evidence of its deleterious effects, including kidney and other organ injury.... (Review)
Review
Acid-related injury from chronic metabolic acidosis is recognized through growing evidence of its deleterious effects, including kidney and other organ injury. Progressive acid accumulation precedes the signature manifestation of chronic metabolic acidosis, decreased plasma bicarbonate concentration. Acid accumulation that is not enough to manifest as metabolic acidosis, known as eubicarbonatemic acidosis, also appears to cause kidney injury, with exacerbated progression of CKD. Chronic engagement of mechanisms to mitigate the acid challenge from Western-type diets also appears to cause kidney injury. Rather than considering chronic metabolic acidosis as the only acid-related condition requiring intervention to reduce kidney injury, this review supports consideration of acid-related injury as a continuum. This "acid stress" continuum has chronic metabolic acidosis at its most extreme end, and high-acid-producing diets at its less extreme, yet detrimental, end.
Topics: Acid-Base Equilibrium; Acidosis; Acids; Bicarbonates; Chronic Disease; Diet; Glomerular Filtration Rate; Humans; Kidney Diseases; Stress, Physiological
PubMed: 33741720
DOI: 10.2215/CJN.17541120 -
Kidney International Jun 2022The homeostatic regulation of a stable systemic pH is of critical importance for mammalian survival. During metabolic acidosis (a reduction in systemic pH caused by a... (Review)
Review
The homeostatic regulation of a stable systemic pH is of critical importance for mammalian survival. During metabolic acidosis (a reduction in systemic pH caused by a primary decrease in serum bicarbonate concentration), as seen in clinical disorders such as the later stages of chronic kidney disease, renal tubular acidosis, or chronic diarrhea, bone buffers the accumulated acid; however, this homeostatic function of the skeleton occurs at the expense of the bone mineral content and leads to decreased bone quality. During short-term studies to model acute metabolic acidosis, there is initial physiochemical bone mineral dissolution, releasing carbonate and phosphate proton buffers into the extracellular fluid. In addition, there is net proton influx into the mineral with release of bone sodium and potassium. During long-term studies to model chronic metabolic acidosis, there is also inhibition of osteoblast activity, resulting in reduced bone formation, and an increase in osteoclast activity, resulting in increased bone resorption and release of calcium and anionic proton buffers. These physicochemical and cell-mediated bone responses to metabolic acidosis, in addition to an acidosis-induced increased urine calcium excretion, without a corresponding increase in intestinal calcium absorption, induce a net loss of body calcium that is almost certainly derived from the mineral stores of bone.
Topics: Acidosis; Animals; Bone and Bones; Calcium; Hydrogen-Ion Concentration; Mammals; Phosphates; Protons
PubMed: 35351460
DOI: 10.1016/j.kint.2022.02.032 -
British Journal of Clinical Pharmacology Dec 2018Massive metformin overdose can cause metabolic acidosis with hyperlactatemia. A 55-year-old woman presented 5 h after multidrug overdose, including 132 g...
Massive metformin overdose can cause metabolic acidosis with hyperlactatemia. A 55-year-old woman presented 5 h after multidrug overdose, including 132 g extended-release metformin. Continuous venovenous haemodiafiltration (CVVHDF) and noradrenaline were commenced due to metabolic acidosis (pH 7.0, lactate 17 mmol l ) and shock. Despite 3 h of CVVHDF, her acidosis worsened (pH 6.83, lactate 24 mmol l ). Intermittent haemodialysis (IHD) improved acidosis (pH 7.13, lactate 26 mmol l ) but again worsened (pH 6.91, lactate 30 mmol l ) with CVVHDF recommencement. IHD (12 h), CVVHDF (26 h) and vasopressor support for 7 days resulted in survival. Measured metformin concentrations were extremely high with a peak of 292 μg ml at 8 h postingestion. IHD, but not CVVHDF in this case, was associated with improvement in metabolic acidosis and hyperlactataemia. Pharmacokinetic analysis of metformin concentrations found a reduced apparent oral clearance of 8.2 l h and a half-life of approximately 30 h. During IHD, the apparent oral clearance increased to 22.2 l h with an approximate half-life of 10 h. The impact of prolonged oral absorption from a pharmacobezoar and redistribution of metformin from peripheral sites (including erythrocytes) on the pharmacokinetic profile cannot be determined from the data available.
Topics: Acidosis; Drug Overdose; Female; Hemodiafiltration; Humans; Hypoglycemic Agents; Metformin; Middle Aged; Renal Dialysis; Tissue Distribution
PubMed: 29534338
DOI: 10.1111/bcp.13582 -
Annals of Hepatology 2022In addition to the kidneys and lungs, the liver also plays an important role in the regulation of the Acid-Base Equilibrium (ABE). The involvement of the liver in the... (Review)
Review
In addition to the kidneys and lungs, the liver also plays an important role in the regulation of the Acid-Base Equilibrium (ABE). The involvement of the liver in the regulation of ABE is crucial because of its role in lactic acid metabolism, urea production and in protein homeostasis. The main acid-base imbalance that occurs in patients with liver cirrhosis is Respiratory Alkalosis (RAlk). Due to the fact that in these patients additional pathophysiological mechanisms that affect the ABE are present, other disorders may appear which compensate or enhance the primary disorder. Conventional ABE reading models fail to identify and assess the underlying disorders in patients with liver cirrhosis. This weakness of the classical models led to the creation of new physicochemical mathematical models that take into account all the known parameters that develop and affect the ABE. In addition to the RAlk, in patients with liver cirrhosis, metabolic alkalosis (due to hypoalbuminemia), hyponatremic metabolic acidosis, hyperchloremic metabolic acidosis, lactic acidosis and metabolic alkalosis due to urea metabolism are some of the pathophysiological mechanisms that affect the ABE.
Topics: Acidosis; Alkalosis; Humans; Liver Cirrhosis; Liver Diseases; Urea
PubMed: 35074477
DOI: 10.1016/j.aohep.2022.100675