Experten-Wissen zur chronischen Azidose

Abstract: Galectin 3 Level is reduced by treatment with sodium bicarbonat in patients with chronic kidney disease.

Background: Circulating cardiac biomarkers implicated in the pathogenesis of heart disease are a non-invasive platform to assess the cardiovascular disease (CVD) burden in individuals with chronic kidney disease (CKD). Galectin 3 is a 26 kDa β-galactoside-binding lectin that has a graded and positive association with CKD stages. In animal models, inhibition of galectin-3 prevents myocardial fibrosis. These pre-clinical findings have not been replicated in randomized controlled studies in humans. Metabolic acidosis of CKD has been shown to be associated with adverse CVD outcomes. We sought to examine whether correction of metabolic acidosis of CKD leads to lower circulating levels of Galectin 3, as an expression of myocardial fibrosis.

Methods: A total of 95 participants with stages 3 and 4 CKD and a serum bicarbonate level between 21-25 mEq/L, were randomized to receive sodium bicarbonate at a dose of 0.4 mEq/kg/day once a day or placebo for two years at two clinical sites in US. Galectin 3, was measured at study baseline and after one year.

Results: Fifty participants were randomized to sodium bicarbonate and 45 to placebo. Mean age (SD) was 61.4 (10.2) years, 48% were women, 57% were non-Hispanic black, and 40% were non-Hispanic white, 61% had diabetes mellitus and 90% had hypertension at baseline. Mean baseline serum bicarbonate level was 23.5 (SD 1.7), mean (SD) baseline eGFR was 38.8 (11.2) ml/min/1.7m2 and mean (SD) baseline systolic BP was 130 (17) mmHg. There were no differences in baseline characteristics between treatment groups. Compared to the placebo group, participants randomized to sodium bicarbonate had statistically significant change in the levels of Galectin 3 after one year of treatment (-7.12% vs 7.76% and -1.25 vs 1.54 ng/ml, p=0.03 in the sodium bicarbonate vs. placebo group, respectively, Figure). In subgroup analyses by CKD stages, participants with stage 3A randomized to sodium bicarbonate observed the highest decrement in Galectin 3 levels (-19.2% vs 14.7%, p=0.01; -3.3% vs -4.8%, p=0.49; and -7.4% vs 29.1%, p=0.09; for CKD 3B, 3B and 4, respectively).

Conclusions: The level of Galectin 3 was reduced in patients with CKD 3 and 4 treated with sodium bicarbonate. This provides a framework for future therapeutic interventions aimed at reduction of myocardial fibrosis in patients with CKD and metabolic acidosis.

Published by Oxford Academics | DOI: gfaa140.MO021

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Abstract: Arterial Stiffness and Chronic Kidney Disease

Chronic kidney disease (CKD) is a major public health concern due to the high prevalence of associated cardiovascular (CV) disease. CV mortality is 10-30 times higher in end-stage renal disease patients than in the age-adjusted general population. The last 20 years have been marked by a huge effort in the characterization of the vascular remodeling process associated with CKD and its consequences on the renal, CV and general prognosis. By comparison with patients with normal renal function, with or without hypertension, an increase in large artery stiffness has been described in end-stage renal disease as well as in CKD stages 2-5. Most clinical studies are consistent with the observation that damage to large arteries may contribute to the high incidence of CV disease. By contrast, the impact of large artery stiffening and remodeling on CKD progression is still a matter of debate. Concomitant exposure to other CV risk factors, including diabetes, seems to play a major role in the association between aortic stiffness and estimated GFR. The conflicting results obtained from longitudinal studies designed to evaluate the impact of baseline aortic stiffness on GFR progression are detailed in the present review. Only pulse pressure, central and peripheral, is almost constantly associated with incident CKD and GFR decline. Kidney transplantation improves patients’ CV prognosis, but its impact on arterial stiffness is still controversial. Donor age, living kidney donation and mean blood pressure appear to be the main determinants of improvement in aortic stiffness after kidney transplantation.

Published by Karger AG Basel | DOI: 10.1159/000443616

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Abstract: Effects of changes of pH on the contractile function of cardiac muscle

It has been known for over 100 years that acidosis decreases the contractility of cardiac muscle. However, the mechanisms underlying this decrease are complicated because acidosis affects every step in the excitation-contraction coupling pathway, including both the delivery of Ca2+ to the myofilaments and the response of the myofilaments to Ca2+. Acidosis has diverse effects on Ca2+ delivery. Actions that may diminish Ca2+ delivery include 1) inhibition of the Ca2+ current, 2) reduction of Ca2+ release from the sarcoplasmic reticulum, and 3) shortening of the action potential, when such shortening occurs. Conversely, Ca2+ delivery may be increased by the prolongation of the action potential that is sometimes observed and by the rise of diastolic Ca2+ that occurs during acidosis. This rise, which will increase the uptake and subsequent release of Ca2+ by the sarcoplasmic reticulum, may be due to 1) stimulation of Na+ entry via Na(+)-Ca2+ exchange; 2) direct inhibition of Na(+)-Ca2+ exchange; 3) mitochondrial release of Ca2+; and 4) displacement of Ca2+ from cytoplasmic buffer sites by H+. Acidosis inhibits myofibrillar responsiveness to Ca2+ by decreasing the sensitivity of the contractile proteins to Ca2+, probably by decreasing the binding of Ca2+ to troponin C, and by decreasing maximum force, possibly by a direct action on the cross bridges. Thus the final amount of force developed by heart muscle during acidosis is the complex sum of these changes.

Published by American Physiological Society | DOI: 10.1152/ajpcell.1990.258.6.C967

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Abstract: Association of Acidemia With Short-Term Mortality of Acute Myocardial Infarction: A Retrospective Study Base on MIMIC-III Database

Acute myocardial infarction (AMI) is a leading cause of death and not a few of these patients are combined with acidemia. This study aimed to detect the association of acidemia with short-term mortality of AMI patients. A total of 972 AMI patients were selected from the Medical Information Mart for Intensive Care (MIMIC) III database for analysis. Propensity-score matching (PSM) was used to reduce the imbalance. Kaplan-Meier survival analysis was used to compare the mortality, and Cox-proportional hazards model was used to detect related factors associated with mortality. After PSM, a total of 345 non-acidemia patients and 345 matched acidemia patients were included. The non-acidemia patients had a significantly lower 30-day mortality (20.0% vs. 28.7%) and lower 90-day mortality (24.9% vs. 31.9%) than the acidemia patients (P < 0.001 for all). The severe-acidemia patients (PH < 7.25) had the highest 30-day mortality (52.6%) and 90-day mortality (53.9%) than non-acidemia patients and mild-acidemia (7.25 ≤ PH < 7.35) patients (P < 0.001). In Cox-proportional hazards model, acidemia was associated with improved 30-day mortality (HR = 1.518; 95%CI = 1.110-2.076, P = 0.009) and 90-day mortality (HR = 1.378; 95%CI = 1.034 -1.837, P = 0.029). These results suggest that severe acidemia is associated with improved 30-day mortality and 90-day mortality of AMI patients.

Published by Sage Journals | DOI: 10.1177/1076029620950837

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Abstract: Disturbed acid-base transport: an emerging cause of hypertension.

Genome-wide association studies and physiological investigations have linked alterations in acid-base transporters to hypertension. Accordingly, Na+-coupled HCO−3-transporters, Na+/H+-exchangers, and anion-exchangers have emerged as putative mechanistic components in blood pressure disturbances. Even though hypertension has been studied extensively over the last several decades, the cause of the high blood pressure has in most cases not been identified. Renal, cardiovascular, and neuronal dysfunctions all seem to play a role in hypertension development but their relative importance and mutual interdependency are still being debated. Multiple functional and structural alterations have been described in patients and animals with hypertension but it is typically unclear whether they are causes or consequences of hypertension or represent mechanistically unrelated associations. Perturbed blood pressure regulation has been demonstrated in several animal models with disrupted expression of acid-base transporters; and reciprocally, disturbed acid-base transport function has been described in hypertensive individuals. In addition to regulating intracellular and extracellular pH, Na+-coupled HCO−3-transport, Na+/H+-exchange, and anion-exchange also contribute to water and electrolyte balance in cells and systemically. Since acid-base transporters are widely expressed, alterations in transport activities likely affect multiple cell and organ functions, and it is a significant challenge to determine the mechanisms linking perturbed acid-base transport function to hypertension. It is the purpose of this review to evaluate the current evidence for involvement of acid-base transporters in hypertension development and discuss the cellular and integrative mechanisms, which may link changes in acid-base transport to blood pressure disturbances.

Published by Frontiers | DOI: 10.3389/fphys.2013.00388

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Abstract: Metabolic and clinical consequences of metabolic acidosis.

Acid-base balance is precisely regulated by pulmonary and renal responses while body buffers help to control pH. When its regulation becomes abnormal, accumulation of hydrogen ions cause metabolic acidosis and several responses are activated. These responses interfere with the metabolism of bones and muscle. Metabolic acidosis induces abnormalities in the release and function of several hormones including defects in growth hormone, IGF-1, insulin, glucocorticoids, thyroid hormone, parathyroid hormone and vitamin D. Clinical consequences of these abnormal metabolic responses include impaired growth of infants and children and loss of bone and muscle mass in adults. Notably, abnormalities in bone and muscle metabolism can be present even when there is little or no decrease in the plasma bicarbonate concentration. The abnormalities can be corrected by treatment with NaHCO 3 . In patients with chronic kidney disease, many abnormalities in bone and muscle metabolism can be directly linked to the presence of metabolic acidosis and these abnormalities can be largely corrected by treating acidosis with NaHCO3. Recent insights indicate that several consequences of metabolic acidosis including the development of insulin resistance can stimulate muscle protein degradation by activating proteolytic mechanisms. To avoid abnormalities in metabolism and the loss of bone and muscle, metabolic acidosis must be corrected in normal adults and in patients with kidney disease.

Published by Springer: Journal of Nephrology | PMID: 16736444

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Abstract: The therapeutic importance of acid-base balance

Baking soda and vinegar have been used as home remedies for generations and today we are only a mouse-click away from claims that baking soda, lemon juice, and apple cider vinegar are miracles cures for everything from cancer to COVID-19. Despite these specious claims, the therapeutic value of controlling acid-base balance is indisputable and is the basis of Food and Drug Administration-approved treatments for constipation, epilepsy, metabolic acidosis, and peptic ulcers. In this narrative review, we present evidence in support of the current and potential therapeutic value of countering local and systemic acid-base imbalances, several of which do in fact involve the administration of baking soda (sodium bicarbonate). Furthermore, we discuss the side effects of pharmaceuticals on acid-base balance as well as the influence of acid-base status on the pharmacokinetic properties of drugs. Our review considers all major organ systems as well as information relevant to several clinical specialties such as anesthesiology, infectious disease, oncology, dentistry, and surgery.

Published by Elsevier Inc. | DOI: 10.1016/j.bcp.2020.114278

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