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Journal of Animal Science Aug 2020Acute and subacute ruminal acidosis (SARA) are common nutritional problems in both beef and dairy cattle. Therefore, the objective of this review is to describe how... (Review)
Review
Acute and subacute ruminal acidosis (SARA) are common nutritional problems in both beef and dairy cattle. Therefore, the objective of this review is to describe how ruminal Gram-negative bacteria could contribute to the pathogenesis of ruminal acidoses, by releasing lipopolysaccharides (LPS; a component of their cell wall) in the ruminal fluid. When cattle consume excessive amounts of highly fermentable carbohydrates without prior adaptation, normal fermentation become disrupted. The fermentation of these carbohydrates quickly decreases ruminal pH due to the accumulation of short-chain fatty acids and lactate in the rumen. As a consequence, ruminal epithelium may be damaged and tissue function could be impaired, leading to a possible translocation of pathogenic substances from the rumen into the bloodstream. Such changes in fermentation are followed by an increase in Gram-positive bacteria while Gram-negative bacteria decrease. The lyses of Gram-negative bacteria during ruminal acidosis increase LPS concentration in the ruminal fluid. Because LPS is a highly proinflammatory endotoxin in the circulatory system, past studies have raised concerns regarding ruminal LPS contribution to the pathogenesis of ruminal acidosis. Although animals that undergo these disorders do not always have an immune response, recent studies showed that different Gram-negative bacteria have different LPS composition and toxicity, which may explain the differences in immune response. Given the diversity of Gram-negative bacteria in the rumen, evaluating the changes in the bacterial community during ruminal acidosis could be used as a way to identify which Gram-negative bacteria are associated with LPS release in the rumen. By identifying and targeting ruminal bacteria with possible pathogenic LPS, nutritional strategies could be created to overcome, or at least minimize, ruminal acidosis.
Topics: Acidosis; Animals; Cattle; Cattle Diseases; Diet; Epithelium; Fatty Acids, Volatile; Fermentation; Gram-Negative Bacteria; Hydrogen-Ion Concentration; Lipopolysaccharides; Rumen
PubMed: 32761212
DOI: 10.1093/jas/skaa248 -
Bioscience Trends Mar 2022Due to continuous bone remodeling, the bone tissue is dynamic and constantly being updated. Bone remodeling is precisely regulated by the balance between... (Review)
Review
Due to continuous bone remodeling, the bone tissue is dynamic and constantly being updated. Bone remodeling is precisely regulated by the balance between osteoblast-induced bone formation and osteoclast-induced bone resorption. As a giant multinucleated cell, formation and activities of osteoclasts are regulated by macrophage colony-stimulating factor (M-CSF), receptor activator of nuclear factor-kappaB ligand (RANKL), and by pathological destabilization of the extracellular microenvironment. Microenvironmental acidosis, as the prime candidate, is a driving force of multiple biological activities of osteoclast precursor and osteoclasts. The mechanisms involved in these processes, especially acid-sensitive receptors/channels, are of great precision and complicated. Recently, remarkable progress has been achieved in the field of acid-sensitive mechanisms of osteoclasts. It is important to elucidate the relationship between microenvironmental acidosis and excessive osteoclasts activity, which will help in understanding the pathophysiology of diseases that are associated with excess bone resorption. This review summarizes physiological consequences and in particular, potential mechanisms of osteoclast precursor or osteoclasts in the context of acidosis microenvironments.
Topics: Acidosis; Biology; Bone Resorption; Cell Differentiation; Humans; Osteoblasts; Osteoclasts; RANK Ligand
PubMed: 34732613
DOI: 10.5582/bst.2021.01357 -
Clinical Journal of the American... Feb 2021
Topics: Acidosis; Ammonium Compounds; Animals; Bicarbonates; Citric Acid; Disease Progression; Humans; Hydrogen-Ion Concentration; Renal Insufficiency, Chronic
PubMed: 32769096
DOI: 10.2215/CJN.07990520 -
Journal of the American Society of... Dec 2016Metabolic acidosis is associated with increased urinary calcium excretion and related sequelae, including nephrocalcinosis and nephrolithiasis. The increased urinary... (Review)
Review
Metabolic acidosis is associated with increased urinary calcium excretion and related sequelae, including nephrocalcinosis and nephrolithiasis. The increased urinary calcium excretion induced by metabolic acidosis predominantly results from increased mobilization of calcium out of bone and inhibition of calcium transport processes within the renal tubule. The mechanisms whereby acid alters the integrity and stability of bone have been examined extensively in the published literature. Here, after briefly reviewing this literature, we consider the effects of acid on calcium transport in the renal tubule and then discuss why not all gene defects that cause renal tubular acidosis are associated with hypercalciuria and nephrocalcinosis.
Topics: Acid-Base Imbalance; Acidosis; Bone Diseases; Calcium; Humans; Hypercalciuria; Kidney Tubules; Nephrocalcinosis
PubMed: 27468975
DOI: 10.1681/ASN.2016030305 -
Cancer Metastasis Reviews Jun 2019While cancer is commonly described as "a disease of the genes," it is also associated with massive metabolic reprogramming that is now accepted as a disease "Hallmark."... (Review)
Review
While cancer is commonly described as "a disease of the genes," it is also associated with massive metabolic reprogramming that is now accepted as a disease "Hallmark." This programming is complex and often involves metabolic cooperativity between cancer cells and their surrounding stroma. Indeed, there is emerging clinical evidence that interrupting a cancer's metabolic program can improve patients' outcomes. The most commonly observed and well-studied metabolic adaptation in cancers is the fermentation of glucose to lactic acid, even in the presence of oxygen, also known as "aerobic glycolysis" or the "Warburg Effect." Much has been written about the mechanisms of the Warburg effect, and this remains a topic of great debate. However, herein, we will focus on an important sequela of this metabolic program: the acidification of the tumor microenvironment. Rather than being an epiphenomenon, it is now appreciated that this acidosis is a key player in cancer somatic evolution and progression to malignancy. Adaptation to acidosis induces and selects for malignant behaviors, such as increased invasion and metastasis, chemoresistance, and inhibition of immune surveillance. However, the metabolic reprogramming that occurs during adaptation to acidosis also introduces therapeutic vulnerabilities. Thus, tumor acidosis is a relevant therapeutic target, and we describe herein four approaches to accomplish this: (1) neutralizing acid directly with buffers, (2) targeting metabolic vulnerabilities revealed by acidosis, (3) developing acid-activatable drugs and nanomedicines, and (4) inhibiting metabolic processes responsible for generating acids in the first place.
Topics: Acidosis; Animals; Buffers; Humans; Hydrogen-Ion Concentration; Neoplasm Invasiveness; Neoplasm Metastasis; Neoplasms
PubMed: 30911978
DOI: 10.1007/s10555-019-09792-7 -
Nephrology, Dialysis, Transplantation :... Dec 2021Metabolic acidosis, defined as a plasma or serum bicarbonate concentration <22 mmol/L, is a frequent consequence of chronic kidney disease (CKD) and occurs in ~10-30% of... (Review)
Review
Metabolic acidosis, defined as a plasma or serum bicarbonate concentration <22 mmol/L, is a frequent consequence of chronic kidney disease (CKD) and occurs in ~10-30% of patients with advanced stages of CKD. Likewise, in patients with a kidney transplant, prevalence rates of metabolic acidosis range from 20% to 50%. CKD has recently been associated with cognitive dysfunction, including mild cognitive impairment with memory and attention deficits, reduced executive functions and morphological damage detectable with imaging. Also, impaired motor functions and loss of muscle strength are often found in patients with advanced CKD, which in part may be attributed to altered central nervous system (CNS) functions. While the exact mechanisms of how CKD may cause cognitive dysfunction and reduced motor functions are still debated, recent data point towards the possibility that acidosis is one modifiable contributor to cognitive dysfunction. This review summarizes recent evidence for an association between acidosis and cognitive dysfunction in patients with CKD and discusses potential mechanisms by which acidosis may impact CNS functions. The review also identifies important open questions to be answered to improve prevention and therapy of cognitive dysfunction in the setting of metabolic acidosis in patients with CKD.
Topics: Acidosis; Bicarbonates; Cognitive Dysfunction; Humans; Motor Disorders; Renal Insufficiency, Chronic
PubMed: 34718761
DOI: 10.1093/ndt/gfab216 -
Archivos Espanoles de Urologia Jan 2021Renal tubular acidosis (RTA) is a set of raredis orders in which the renal tubule is unable to excreteacid normally and there by maintain normal acid-basebalance,...
Renal tubular acidosis (RTA) is a set of raredis orders in which the renal tubule is unable to excreteacid normally and there by maintain normal acid-basebalance, resulting in a complete or incomplete metabolicacidosis. In distal RTA (dRTA, also known as classicalor type 1 RTA), there is a defect in excreting H+ ionsalong the distal nephron (distal tubule and collectingduct), leading to an alkaline urinary pH with calcium phosphate precipitation and stones. Causes of dRTAinclude genetic mutations, autoimmune disease, and some drugs.Clinical manifestations of the genetic forms of dRTA typically occur during childhood and may vary from mildclinical symptoms, such as a mild metabolic acidosis, hypokalaemia,and incidental detection of kidney stones, to more serious manifestations such as failure to thrive,severe metabolic acidosis, rickets and nephrocalcinosis.Progressive hearing loss may develop in patients withrecessive dRTA, which, depending the causative genemutation, can be present at birth or develop later in adolescence or early adulthood. Diagnosis of dRTA can be challenging, since it requires a high index of suspicion and/or measurement of urinary pH after an acid load, usually in the form of oral ammonium chloride; this should normally acidify the urine to pH below 5.3. In dRTA, urinary citrate levels a real so low and patients are at increased risk of for mingkidney stones from a combination of alkaline urine and low citrate. Ideally, affected patients need regular outpatient follow-up by a urologist and nephrologist. Thus, any patient found to have a calcium phosphate kidney stone, low urinary citrate, and raised urinary pH, especially with an early morning pH >5.5, should be evaluated for underlying dRTA. Patients with complete dRTA will have a low (<20 mmol/L) plasma or serum bicarbonate concentration, whereas in those with incomplete dRTA, bicarbonate levels are usually normal. Oral alkali as potassiumcitrate is still the mainstay of treatment in dRTA.
Topics: Acidosis, Renal Tubular; Adolescent; Adult; Ammonium Chloride; Child; Citric Acid; Humans; Hydrogen-Ion Concentration; Kidney Calculi
PubMed: 33459628
DOI: No ID Found -
Cancer Metastasis Reviews Jun 2019Skeletal involvement is a frequent and troublesome complication in advanced cancers. In the process of tumor cells homing to the skeleton to form bone metastases (BM),... (Review)
Review
Skeletal involvement is a frequent and troublesome complication in advanced cancers. In the process of tumor cells homing to the skeleton to form bone metastases (BM), different mechanisms allow tumor cells to interact with cells of the bone microenvironment and seed in the bone tissue. Among these, tumor acidosis has been directly associated with tumor invasion and aggressiveness in several types of cancer although it has been less explored in the context of BM. In bone, the association of local acidosis and cancer invasiveness is even more important for tumor expansion since the extracellular matrix is formed by both organic and hard inorganic matrices and bone cells are used to sense protons and adapt or react to a low pH to maintain tissue homeostasis. In the BM microenvironment, increased concentration of protons may derive not only from glycolytic tumor cells but also from tumor-induced osteoclasts, the bone-resorbing cells, and may influence the progression or symptoms of BM in many different ways, by directly enhancing cancer cell motility and aggressiveness, or by modulating the functions of bone cells versus a pro-tumorigenic phenotype, or by inducing bone pain. In this review, we will describe and discuss the cause of acidosis in BM, its role in BM microenvironment, and which are the final effectors that may be targeted to treat metastatic patients.
Topics: Acidosis; Animals; Bone Neoplasms; Breast Neoplasms; Female; Humans; Tumor Microenvironment
PubMed: 30825056
DOI: 10.1007/s10555-019-09790-9 -
Journal of the American Society of... Mar 2015Metabolic acidosis was one of the earliest complications to be recognized and explained pathologically in patients with CKD. Despite the accumulated evidence of... (Review)
Review
Metabolic acidosis was one of the earliest complications to be recognized and explained pathologically in patients with CKD. Despite the accumulated evidence of deleterious effects of acidosis, treatment of acidosis has been tested very little, especially with respect to standard clinical outcomes. On the basis of fundamental research and small alkali supplementation trials, correcting metabolic acidosis has a strikingly broad array of potential benefits. This review summarizes the published evidence on the association between serum bicarbonate and clinical outcomes. We discuss the role of alkali supplementation in CKD as it relates to retarding kidney disease progression, improving metabolic and musculoskeletal complications.
Topics: Acidosis; Alkalies; Animals; Bicarbonates; Cardiovascular Diseases; Dietary Supplements; Humans; Renal Insufficiency, Chronic
PubMed: 25150154
DOI: 10.1681/ASN.2014020205 -
Clinical Medicine (London, England) Nov 2023Lactic acidosis is commonly associated with tissue hypoperfusion and gives rise to concern regarding hypoxia or underlying hypotension. In the cancer patient, especially...
Lactic acidosis is commonly associated with tissue hypoperfusion and gives rise to concern regarding hypoxia or underlying hypotension. In the cancer patient, especially one undergoing chemotherapy, there is always concern for sepsis; however, in the otherwise clincially stable patient with cancer, type B lactic acidosis can also be related to their underlying malignancy. It is considered a haematological emergency given its high mortality rate. However, despite the urgency to treat type B lactic acidosis in these circumstances, treatment options beyond treatment of the malignancy are limited, and its presence portends a poor prognosis. This case highlights our current understanding of type B lactic acidosis and an approach to lactic acidosis evaluation in the cancer patient.
Topics: Humans; Acidosis, Lactic; Neoplasms; Sepsis
PubMed: 38065594
DOI: 10.7861/clinmed.2023-0391