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Medical Oncology (Northwood, London,... Oct 2018Metabolic alterations in the tumor microenvironment have a complex effect on cancer progression. Extracellular acidity is a consequence of metabolic switch in cancer and...
Metabolic alterations in the tumor microenvironment have a complex effect on cancer progression. Extracellular acidity is a consequence of metabolic switch in cancer and results in cell phenotypes with higher resistance to chemotherapeutics. However, mechanisms underlying the relationship between the extracellular acidity and chemoresistance are not clearly understood. This systematic review was carried out by searching the databases PubMed and EMBASE using the keywords "cancer" and "acidosis" or "acidic" and "chemoresistance" or "drug resistance." In vitro and in vivo studies that evaluated the effects of acidification of the tumor microenvironment on chemotherapeutic treatments were included. Literature reviews, letters to the editor, and articles that were not published in English were excluded. The search resulted in a total of 352 articles. After discarding 75 duplicate references, 277 articles were analyzed by sequentially reading through their titles, abstracts, and finally full-text. A total of 14 articles was selected. Acidification of the tumor microenvironment can trigger resistance through different mechanisms, such as increase in drug efflux transporters, inhibition of proton pumps, induction of the unfolded protein response (UPR), and cellular autophagy.
Topics: Animals; Antineoplastic Agents; Autophagy; Drug Resistance, Neoplasm; Humans; Hydrogen-Ion Concentration; Membrane Transport Proteins; Neoplasms; Tumor Microenvironment; Unfolded Protein Response
PubMed: 30377828
DOI: 10.1007/s12032-018-1214-4 -
The Cochrane Database of Systematic... Oct 2018Biocompatible peritoneal dialysis (PD) solutions, including neutral pH, low glucose degradation product (GDP) solutions and icodextrin, have previously been shown to... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Biocompatible peritoneal dialysis (PD) solutions, including neutral pH, low glucose degradation product (GDP) solutions and icodextrin, have previously been shown to favourably influence some patient-level outcomes, albeit based on generally sub-optimal quality studies. Several additional randomised controlled trials (RCT) evaluating biocompatible solutions in PD patients have been published recently. This is an update of a review first published in 2014.
OBJECTIVES
This review aimed to look at the benefits and harms of biocompatible PD solutions in comparison to standard PD solutions in patients receiving PD.
SEARCH METHODS
The Cochrane Kidney and Transplant Specialised Register was searched up to 12 February 2018 through contact with the Information Specialist using search terms relevant to this review. Studies in the Specialised Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register Search Portal and ClinicalTrials.gov.
SELECTION CRITERIA
All RCTs and quasi-RCTs in adults and children comparing the effects of biocompatible PD solutions (neutral pH, lactate-buffered, low GDP; neutral pH, bicarbonate(± lactate)-buffered, low GDP; glucose polymer (icodextrin)) in PD were included. Studies of amino acid-based solutions were excluded.
DATA COLLECTION AND ANALYSIS
Two authors extracted data on study quality and outcomes. Summary effect estimates were obtained using a random-effects model, and results were expressed as risk ratios and 95% confidence intervals (CI) for categorical variables, and mean differences (MD) or standardised mean differences (SMD) and 95% CI for continuous variables.
MAIN RESULTS
This review update included 42 eligible studies (3262 participants), including six new studies (543 participants). Overall, 29 studies (1971 participants) compared neutral pH, low GDP PD solution with conventional PD solution, and 13 studies (1291 participants) compared icodextrin with conventional PD solution. Risk of bias was assessed as high for sequence generation in three studies, allocation concealment in three studies, attrition bias in 21 studies, and selective outcome reporting bias in 16 studies.Neutral pH, low GDP versus conventional glucose PD solutionUse of neutral pH, low GDP PD solutions improved residual renal function (RRF) preservation (15 studies, 835 participants: SMD 0.19, 95% CI 0.05 to 0.33; high certainty evidence). This approximated to a mean difference in glomerular filtration rate of 0.54 mL/min/1.73 m (95% CI 0.14 to 0.93). Better preservation of RRF was evident at all follow-up durations with progressively greater preservation observed with increasing follow up duration. Neutral pH, low GDP PD solution use also improved residual urine volume preservation (11 studies, 791 participants: MD 114.37 mL/day, 95% CI 47.09 to 181.65; high certainty evidence). In low certainty evidence, neutral pH, low GDP solutions may make little or no difference to 4-hour peritoneal ultrafiltration (9 studies, 414 participants: SMD -0.42, 95% CI -0.74 to -0.10) which approximated to a mean difference in peritoneal ultrafiltration of 69.72 mL (16.60 to 122.00 mL) lower, and may increase dialysate:plasma creatinine ratio (10 studies, 746 participants: MD 0.01, 95% CI 0.00 to 0.03), technique failure or death compared with conventional PD solutions. It is uncertain whether neutral pH, low GDP PD solution use led to any differences in peritonitis occurrence, hospitalisation, adverse events (6 studies, 519 participants) or inflow pain (1 study, 58 participants: RR 0.51, 95% CI 0.24 to 1.08).Glucose polymer (icodextrin) versus conventional glucose PD solutionIn moderate certainty evidence, icodextrin probably reduced episodes of uncontrolled fluid overload (2 studies, 100 participants: RR 0.30, 95% CI 0.15 to 0.59) and augmented peritoneal ultrafiltration (4 studies, 102 participants: MD 448.54 mL/d, 95% CI 289.28 to 607.80) without compromising RRF (4 studies, 114 participants: SMD 0.12, 95% CI -0.26 to 0.49; low certainty evidence) which approximated to a mean creatinine clearance of 0.30 mL/min/1.73m higher (0.65 lower to 1.23 higher) or urine output (3 studies, 69 participants: MD -88.88 mL/d, 95% CI -356.88 to 179.12; low certainty evidence). It is uncertain whether icodextrin use led to any differences in adverse events (5 studies, 816 participants) technique failure or death.
AUTHORS' CONCLUSIONS
This updated review strengthens evidence that neutral pH, low GDP PD solution improves RRF and urine volume preservation with high certainty. These effects may be related to increased peritoneal solute transport and reduced peritoneal ultrafiltration, although the evidence for these outcomes is of low certainty due to significant heterogeneity and suboptimal methodological quality. Icodextrin prescription increased peritoneal ultrafiltration and mitigated uncontrolled fluid overload with moderate certainty. The effects of either neutral pH, low GDP solution or icodextrin on peritonitis, technique survival and patient survival remain uncertain and require further high quality, adequately powered RCTs.
Topics: Adult; Bicarbonates; Child; Dialysis Solutions; Glucose; Humans; Hydrogen-Ion Concentration; Icodextrin; Kidney; Peritoneal Dialysis; Peritoneum; Pharmaceutical Solutions; Randomized Controlled Trials as Topic; Urine
PubMed: 30362116
DOI: 10.1002/14651858.CD007554.pub3 -
Circulation Oct 2018Among his major cardiac electrophysiological contributions, Miles Vaughan Williams (1918-2016) provided a classification of antiarrhythmic drugs that remains central to...
BACKGROUND
Among his major cardiac electrophysiological contributions, Miles Vaughan Williams (1918-2016) provided a classification of antiarrhythmic drugs that remains central to their clinical use.
METHODS
We survey implications of subsequent discoveries concerning sarcolemmal, sarcoplasmic reticular, and cytosolic biomolecules, developing an expanded but pragmatic classification that encompasses approved and potential antiarrhythmic drugs on this centenary of his birth.
RESULTS
We first consider the range of pharmacological targets, tracking these through to cellular electrophysiological effects. We retain the original Vaughan Williams Classes I through IV but subcategorize these divisions in light of more recent developments, including the existence of Na current components (for Class I), advances in autonomic (often G protein-mediated) signaling (for Class II), K channel subspecies (for Class III), and novel molecular targets related to Ca homeostasis (for Class IV). We introduce new classes based on additional targets, including channels involved in automaticity, mechanically sensitive ion channels, connexins controlling electrotonic cell coupling, and molecules underlying longer-term signaling processes affecting structural remodeling. Inclusion of this widened range of targets and their physiological sequelae provides a framework for a modernized classification of established antiarrhythmic drugs based on their pharmacological targets. The revised classification allows for the existence of multiple drug targets/actions and for adverse, sometimes actually proarrhythmic, effects. The new scheme also aids classification of novel drugs under investigation.
CONCLUSIONS
We emerge with a modernized classification preserving the simplicity of the original Vaughan Williams framework while aiding our understanding and clinical management of cardiac arrhythmic events and facilitating future developments in this area.
Topics: Action Potentials; Animals; Anti-Arrhythmia Agents; Arrhythmias, Cardiac; Calcium Channel Blockers; Heart Conduction System; Heart Rate; Humans; Ion Channels; Membrane Transport Modulators; Neurotransmitter Agents; Potassium Channel Blockers; Terminology as Topic; Voltage-Gated Sodium Channel Blockers
PubMed: 30354657
DOI: 10.1161/CIRCULATIONAHA.118.035455 -
Drug Delivery Nov 2018To achieve sufficient blood-brain barrier (BBB), penetration is one of the biggest challenges in the development of diagnostic and therapeutic for central nervous system... (Meta-Analysis)
Meta-Analysis
Borneol, a messenger agent, improves central nervous system drug delivery through enhancing blood-brain barrier permeability: a preclinical systematic review and meta-analysis.
To achieve sufficient blood-brain barrier (BBB), penetration is one of the biggest challenges in the development of diagnostic and therapeutic for central nervous system (CNS) disorders. Here, we conducted a systematic review and meta-analysis to assess the preclinical evidence and possible mechanisms of borneol for improving co-administration of CNS drug delivery in animal models. The electronic literature search was conducted in six databases. Fifty-eight studies with 63 comparisons involved 1137 animals were included. Among 47 studies reporting the assessments of CNS drug concentration, 45 studies showed the significant effects of borneol for improving CNS drug delivery (p<.05), whereas 2 studies showed no difference (p>.05). Nineteen comparisons showed borneol up-regulated BBB permeability (p<.05) using brain EB content (n = 8), Rh 123 content (n = 4), brain imaging agent content (n = 2), brain water content (n = 1) and observing ultrastructure of BBB (n = 4), whereas three studies showed no difference or unclear results. Seven studies reported the safety, in which one study showed borneol was reversible changes in the BBB penetration; six studies showed borneol did not increase co-administration of blood drugs concentration of peripheral tissues (p > .05). Effects of borneol are closely associated with inhibition of efflux protein function, releasement of tight junction protein, increasement of vasodilatory neurotransmitters, and inhibition of active transport by ion channels. In conclusion, borneol is a promising candidate for CNS drug delivery, mainly through mediating a multi-targeted BBB permeability.
Topics: Animals; Blood-Brain Barrier; Camphanes; Central Nervous System Agents; Central Nervous System Diseases; Drug Carriers; Female; Humans; Male; Permeability
PubMed: 30334462
DOI: 10.1080/10717544.2018.1486471 -
Reproductive Biology and Endocrinology... Aug 2017The Catsper channel is a sperm-specific, Ca-permeable, pH-dependent, and low voltage-dependent channel that is essential for the hyperactivity of sperm flagellum,... (Review)
Review
The Catsper channel is a sperm-specific, Ca-permeable, pH-dependent, and low voltage-dependent channel that is essential for the hyperactivity of sperm flagellum, chemotaxis towards the egg, capacitation and acrosome reaction. All of these physiological events require calcium entry into sperm cells. Remarkably, Catsper genes are exclusively expressed in the testis during spermatogenesis, and are sensitive to ion channel-induced pH change, such as NHEs, CaATPase, K channel, Hv1 channel and HCO transporters. Furthermore, the Catsper channel is regulated by some physiological stimulants, such as progesterone, cyclic nucleotides (e.g., cAMP, cGMP), zona pellucida (ZP) glycoproteins and bovine serum albumin (BSA). All of these factors normally stimulate Ca entry into sperm through the Catsper channel. In addition, the Catsper channel may be a potential target for male infertility treatment or contraception. This review will focus on the structure, functions, regulation mechanisms and medicinal targets of the Catsper channel.
Topics: Animals; Calcium Channels; Calcium Signaling; Humans; Hydrogen-Ion Concentration; Infertility, Male; Male; Mice; Spermatozoa
PubMed: 28810916
DOI: 10.1186/s12958-017-0281-2 -
Journal of the Science of Food and... Mar 2018Dairy milk consists of more than 85% water. Therefore, understanding the regulation of fluid absorption in the mammary gland is relevant to improving milk production. In... (Review)
Review
Dairy milk consists of more than 85% water. Therefore, understanding the regulation of fluid absorption in the mammary gland is relevant to improving milk production. In recent decades, studies using different approaches, including blood flow, transmembrane fluid flow, tight junction, fluid flow of the paracellular pathway and functional mammary epithelial cell state, have been conducted aiming to investigate how mammary gland fluid absorption is regulated. However, the relationship between regulation mechanisms of fluid flow and milk production has not been studied systematically. The present review summarizes a series of key milk yield regulatory factors mediated by whole-mammary fluid flow, including milk, mammary blood flow, blood/tissue fluid-cell fluid flow and cell-alveolus fluid flow. Whole-mammary fluid flow regulates milk production by altering transporter activity, ion channels, local microcirculation-related factors, driving force of fluid transport (osmotic pressure or electrochemical gradient), cellular connection state and a cell volume sensitive mechanism. In addition, whole-mammary fluid flow plays important roles in milk synthesis and secretion. Knowledge gained from fluid flow-mediated regulatory mechanisms of the dairy mammary gland will lead to a fundamental understanding of lactation biology and will be beneficial for the improvement of dairy productivity. © 2017 Society of Chemical Industry.
Topics: Animals; Biological Transport; Body Fluids; Cattle; Dairying; Female; Homeostasis; Humans; Lactation; Mammary Glands, Animal; Microcirculation; Milk; Regional Blood Flow; Tight Junctions
PubMed: 28758674
DOI: 10.1002/jsfa.8605 -
Current Pharmaceutical Design 2017Zinc is a critical metal ion essential for life. The biological significance of zinc is highlighted by the enormous number of proteins (approximately 10% of the human... (Review)
Review
BACKGROUND
Zinc is a critical metal ion essential for life. The biological significance of zinc is highlighted by the enormous number of proteins (approximately 10% of the human proteome) that have zinc-binding capacity. Accordingly, zinc concentrations in cells are tightly regulated by two families of zinc transporter proteins: Slc30a (ZnT) and Slc39a (Zip). ZnT and Zip are known to decrease and increase cytosolic zinc concentrations respectively. Both zinc transporters are suggested to be implicated in a number of disorders and disease states through dysfunctional zinc transport including cancer, diabetes and gastrointestinal (GI) disease.
METHOD
The goal of this work was to identify the role of zinc transporters in GI disease/disorders. Where possible, reference will be made in the context of the function of zinc transporters and their potential role in GI disorders/ diseases with a view towards their possible therapeutic utility in the treatment of these ailments. PubMed was utilized to search for articles with the terms "zinc and GI disease", "zinc transporters and GI disease", "zinc and gut", zinc transporters and gut", and "zinc transporters and intestinal disorders".
RESULTS
We identified a number of reviews on GI disorders/disease states associated with zinc deficiencies, but the very proteins that transport this metal ion in these systems are not well-defined. From a systematic review, we identified the following zinc transporters (Zip1, 2, 4-7, 10, 11 and 14; and ZnT1, 8 and 10) as having some functional role in the GI system and potentially could have a therapeutic role in the treatment of GI disease/disorders.
CONCLUSION
An increasingly common health issue in our communities is disorder/disease of the GI system. Although therapies targeting these disorders are somewhat beneficial, there is a need to develop better, more efficient treatments. Despite that many gut-related disorders/disease states have been analyzed in the context of zinc deficiencies, the transport proteins that move zinc across cells are not well-defined. Zinc transporters are expressed in a range of GI tissue and cells, and their roles in the maintenance, integrity and disease processes of the GI system need to be addressed. This might open a whole new avenue of opportunities for the development of novel therapies targeting these receptors in GI disease states.
Topics: Carrier Proteins; Gastrointestinal Diseases; Humans; Zinc
PubMed: 28120719
DOI: 10.2174/1381612823666170124115850 -
The Cochrane Database of Systematic... Jun 2016Cystic fibrosis is caused by a defective gene encoding a protein called the cystic fibrosis transmembrane conductance regulator (CFTR), and is characterised by chronic... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Cystic fibrosis is caused by a defective gene encoding a protein called the cystic fibrosis transmembrane conductance regulator (CFTR), and is characterised by chronic lung infection resulting in inflammation and progressive lung damage that results in a reduced life expectancy.
OBJECTIVES
To determine whether topical CFTR gene replacement therapy to the lungs in people with cystic fibrosis is associated with improvements in clinical outcomes, and to assess any adverse effects.
SEARCH METHODS
We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches, handsearching relevant journals and abstract books of conference proceedings.Date of most recent search: 05 May 2016.An additional search of the National Institutes for Health (NIH) Genetic Modification Clinical Research Information System (GeMCRIS) was also performed for the years 1992 to 2015.Date of most recent search: 20 April 2016.
SELECTION CRITERIA
Randomised controlled studies comparing topical CFTR gene delivery to the lung, using either viral or non-viral delivery systems, with placebo or an alternative delivery system in people with confirmed cystic fibrosis.
DATA COLLECTION AND ANALYSIS
The authors independently extracted data and assessed study quality. Authors of included studies were contacted and asked for any available additional data. Meta-analysis was limited due to differing study designs.
MAIN RESULTS
Four randomised controlled studies met the inclusion criteria for this review, involving a total of 302 participants lasting from 29 days to 13 months; 14 studies were excluded. The included studies differed in terms of CFTR gene replacement agent and study design, which limited the meta-analysis. One study only enrolled adult males, the remaining studies included both males and females aged 12 years and over.Risk of bias in the studies was moderate. Random sequence generation and allocation concealment was only described in the more recent study; the remaining three studies were judged to have an unclear risk of bias. All four studies documented double-blinding to the intervention, but there is some uncertainty with regards to participant blinding in one study. Some outcome data were missing from all four studies.There were no differences in either the number of respiratory exacerbations or the number of participants with an exacerbation between replacement therapy or placebo groups at any time point. Meta-analysis of most respiratory function tests showed no difference between treatment and placebo groups, but the smallest study (n = 16) reported forced vital capacity (litres) increased more in the placebo group at up to 24 hours. A further study reported a significant improvement in forced expiratory volume at one second (litres) at 30 days after participants had received their first dose of favouring the gene therapy agent, but this finding was not confirmed when combined with at second study in the meta-analysis. The more recent study (n = 140) demonstrated a small improvement in forced vital capacity (per cent predicted) at two and three months and again at 11 and 12 months for participants receiving CFTR gene replacement therapy compared to those receiving placebo. The same study reported a significant difference in the relative change in forced expiratory volume at one second (per cent predicted) at two months, three months and 12 months.One small study reported significant concerns with "influenza-like" symptoms in participants treated with CFTR gene replacement therapy; this was not reported on repeated use of the same agent in a larger recent study.There was no other evidence of positive impact on outcomes, in particular improved quality of life or reduced treatment burden.Two studies measured ion transport in the lower airways; one (n = 16) demonstrated significant changes toward normal values in the participants who received gene transfer agents (P < 0.0001), mean difference 6.86 (95% confidence interval 3.77 to 9.95). The second study (n = 140) also reported significant changes toward normal values (P = 0.032); however, aggregate data were not available for analysis. In the most recent study, there was also evidence of increased salt transport in cells obtained by brushing the lower airway. These outcomes, whilst important, are not of direct clinical relevance.
AUTHORS' CONCLUSIONS
One study of liposome-based CFTR gene transfer therapy demonstrated some improvements in respiratory function in people with CF, but this limited evidence of efficacy does not support this treatment as a routine therapy at present. There was no evidence of efficacy for viral-mediated gene delivery.Future studies need to investigate clinically important outcome measures.
Topics: Adolescent; Adult; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Female; Gene Transfer Techniques; Genetic Therapy; Humans; Liposomes; Male; Randomized Controlled Trials as Topic; Respiratory Function Tests; Targeted Gene Repair
PubMed: 27314455
DOI: 10.1002/14651858.CD005599.pub5 -
Journal of Stroke and Cerebrovascular... Jun 2016Brain edema formation is a major cause of brain damages and the high mortality of ischemic stroke. The aim of this review is to explore the relationship between ischemic... (Review)
Review
BACKGROUND
Brain edema formation is a major cause of brain damages and the high mortality of ischemic stroke. The aim of this review is to explore the relationship between ischemic brain edema formation and vasopressin (VP) hypersecretion in addition to the oxygen and glucose deprivation and the ensuing reperfusion injury.
METHODS
Pertinent studies involving ischemic stroke, brain edema formation, astrocytes, and VP were identified by a search of the PubMed and the Web of Science databases in January 2016. Based on clinical findings and reports of animal experiments using ischemic stroke models, this systematic review reanalyzes the implication of individual reports in the edema formation and then establishes the inherent links among them.
RESULTS
This systematic review reveals that cytotoxic edema and vasogenic brain edema in classical view are mainly under the influence of a continuous malfunction of astrocytic plasticity. Adaptive VP secretion can modulate membrane ion transport, water permeability, and blood-brain barrier integrity, which are largely via changing astrocytic plasticity. Maladaptive VP hypersecretion leads to disruptions of ion and water balance across cell membranes as well as the integrity of the blood-brain barrier. This review highlights our current understandings of the cellular mechanisms underlying ischemic brain edema formation and its association with VP hypersecretion.
CONCLUSIONS
VP hypersecretion promotes brain edema formation in ischemic stroke by disrupting hydromineral balance in the neurovascular unit; suppressing VP hypersecretion has the potential to alleviate ischemic brain edema.
Topics: Animals; Astrocytes; Brain; Brain Edema; Brain Ischemia; Humans; Phenotype; Prognosis; Risk Factors; Signal Transduction; Stroke; Up-Regulation; Vasopressins
PubMed: 27068863
DOI: 10.1016/j.jstrokecerebrovasdis.2016.02.002 -
American Journal of Physiology.... Apr 2016Inflammatory bowel disease (IBD) is a chronic inflammatory disorder with a complex pathogenesis. Diarrhea is a highly prevalent and often debilitating symptom of IBD... (Review)
Review
Inflammatory bowel disease (IBD) is a chronic inflammatory disorder with a complex pathogenesis. Diarrhea is a highly prevalent and often debilitating symptom of IBD patients that results, at least in part, from an intestinal hydroelectrolytic imbalance. Evidence suggests that reduced electrolyte absorption is more relevant than increased secretion to this disequilibrium. This systematic review analyses and integrates the current evidence on the roles of epithelial Na(+)-K(+)-ATPase (NKA), Na(+)/H(+) exchangers (NHEs), epithelial Na(+) channels (ENaC), and K(+) channels (KC) in IBD-associated diarrhea. NKA is the key driving force of the transepithelial ionic transport and its activity is decreased in IBD. In addition, the downregulation of apical NHE and ENaC and the upregulation of apical large-conductance KC all contribute to the IBD-associated diarrhea by lowering sodium absorption and/or increasing potassium secretion.
Topics: Animals; Epithelial Cells; Epithelial Sodium Channels; Gastrointestinal Absorption; Gastrointestinal Agents; Humans; Inflammatory Bowel Diseases; Intestinal Mucosa; Ion Transport; Membrane Transport Modulators; Potassium Channels; Signal Transduction; Sodium-Hydrogen Exchangers; Sodium-Potassium-Exchanging ATPase
PubMed: 26744474
DOI: 10.1152/ajpgi.00369.2015