1
|
Pingili S, Makkena VK, Jaramillo AP, Awosusi BL, Ayyub J, Dabhi KN, Gohil NV, Tanveer N, Hussein S, Hamid P. The Role of Non-genetic Therapies to Reduce the Incidence of Sickle Cell Crisis: A Systematic Review. Cureus 2023; 15:e42785. [PMID: 37664256 PMCID: PMC10469705 DOI: 10.7759/cureus.42785] [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: 07/10/2023] [Accepted: 07/31/2023] [Indexed: 09/05/2023] Open
Abstract
Sickle cell anemia is a hemoglobinopathy that causes complications such as Vaso-Occlusive Crisis (VOC), stroke, priapism, Acute Chest Syndromes (ACS), and bone infarcts due to blood vessel occlusion, resulting in hypoxia, ischemia, and inflammation. Preventing these incidents improves the quality of life and lowers mortality rates in Sickle Cell Disease (SCD) patients. This systematic review aims to describe the drugs, their mechanisms of action, dosages, changes in hemoglobin parameters, decrease in VOCs, delay the time for the next VOC, decrease in the length of hospital stay, and side effects associated with these drugs. This review adheres to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) 2020 guidelines. For this review, we searched the PubMed, Google Scholar, and Cochrane databases and screened them for full free texts published in English and studied in humans in the last five years beginning in 2018. Randomized clinical trials (RCT), observational studies, meta-analyses, systemic reviews, and traditional reviews were all included in the search. According to the type of study, quality assessment tools are used, and eight papers are chosen. Full-text articles from these papers are studied, analyzed, and tabulated. We discussed seven interventions that are used to treat sickle cell disease. Voxelotor, crizanlizumab, L-glutamate, long-term blood transfusions, Zinc (Zn), Niprisan®, and Ciklavit* were found to reduce the number and severity of VOC. We discovered that VOCs containing L -glutamate reduced the length of hospitalization. Magnesium (Mg) did not affect the number and severity of VOCs. This review includes a few articles for the study. Future papers on this subject should include a large sample size and many papers. More clinical trials are required to evaluate the dosages and outcomes of using these drugs in combination to prevent VOCs.
Collapse
Affiliation(s)
- Shravya Pingili
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Vijaya Krishna Makkena
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Arturo P Jaramillo
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Babatope L Awosusi
- Pathology and Laboratory Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Javaria Ayyub
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Karan Nareshbhai Dabhi
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Namra V Gohil
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Nida Tanveer
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Sally Hussein
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Pousette Hamid
- Neurology, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| |
Collapse
|
2
|
Gibson JS, Rees DC. Emerging drug targets for sickle cell disease: shedding light on new knowledge and advances at the molecular level. Expert Opin Ther Targets 2023; 27:133-149. [PMID: 36803179 DOI: 10.1080/14728222.2023.2179484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
INTRODUCTION In sickle cell disease (SCD), a single amino acid substitution at β6 of the hemoglobin (Hb) chain replaces glutamate with valine, forming HbS instead of the normal adult HbA. Loss of a negative charge, and the conformational change in deoxygenated HbS molecules, enables formation of HbS polymers. These not only distort red cell morphology but also have other profound effects so that this simple etiology belies a complex pathogenesis with multiple complications. Although SCD represents a common severe inherited disorder with life-long consequences, approved treatments remain inadequate. Hydroxyurea is currently the most effective, with a handful of newer treatments, but there remains a real need for novel, efficacious therapies. AREAS COVERED This review summarizes important early events in pathogenesis to highlight key targets for novel treatments. EXPERT OPINION A thorough understanding of early events in pathogenesis closely associated with the presence of HbS is the logical starting point for identification of new targets rather than concentrating on more downstream effects. We discuss ways of reducing HbS levels, reducing the impact of HbS polymers, and of membrane events perturbing cell function, and suggest using the unique permeability of sickle cells to target drugs specifically into those more severely compromised.
Collapse
Affiliation(s)
- John S Gibson
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - David C Rees
- Department of Paediatric Haematology, King's College Hospital, London, UK
| |
Collapse
|
3
|
Monedero Alonso D, Pérès L, Hatem A, Bouyer G, Egée S. The Chloride Conductance Inhibitor NS3623 Enhances the Activity of a Non-selective Cation Channel in Hyperpolarizing Conditions. Front Physiol 2021; 12:743094. [PMID: 34707512 PMCID: PMC8543036 DOI: 10.3389/fphys.2021.743094] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 09/13/2021] [Indexed: 12/29/2022] Open
Abstract
Handbooks of physiology state that the strategy adopted by red blood cells (RBCs) to preserve cell volume is to maintain membrane permeability for cations at its minimum. However, enhanced cation permeability can be measured and observed in specific physiological and pathophysiological situations such as in vivo senescence, storage at low temperature, sickle cell anemia and many other genetic defects affecting transporters, membrane or cytoskeletal proteins. Among cation pathways, cation channels are able to dissipate rapidly the gradients that are built and maintained by the sodium and calcium pumps. These situations are very well-documented but a mechanistic understanding of complex electrophysiological events underlying ion transports is still lacking. In addition, non-selective cation (NSC) channels present in the RBC membrane have proven difficult to molecular identification and functional characterization. For instance, NSC channel activity can be elicited by Low Ionic Strength conditions (LIS): the associated change in membrane potential triggers its opening in a voltage dependent manner. But, whereas this depolarizing media produces a spectacular activation of NSC channel, Gárdos channel-evoked hyperpolarization's have been shown to induce sodium entry through a pathway thought to be conductive and termed Pcat. Using the CCCP method, which allows to follow fast changes in membrane potential, we show here (i) that hyperpolarization elicited by Gárdos channel activation triggers sodium entry through a conductive pathway, (ii) that chloride conductance inhibition unveils such conductive cationic conductance, (iii) that the use of the specific chloride conductance inhibitor NS3623 (a derivative of Neurosearch compound NS1652), at concentrations above what is needed for full anion channel block, potentiates the non-selective cation conductance. These results indicate that a non-selective cation channel is likely activated by the changes in the driving force for cations rather than a voltage dependence mechanism per se.
Collapse
Affiliation(s)
- David Monedero Alonso
- Sorbonne Université, CNRS, UMR LBI2M, Station Biologique de Roscoff SBR, Roscoff, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Laurent Pérès
- Sorbonne Université, CNRS, UMR LBI2M, Station Biologique de Roscoff SBR, Roscoff, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Aline Hatem
- Sorbonne Université, CNRS, UMR LBI2M, Station Biologique de Roscoff SBR, Roscoff, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Guillaume Bouyer
- Sorbonne Université, CNRS, UMR LBI2M, Station Biologique de Roscoff SBR, Roscoff, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Stéphane Egée
- Sorbonne Université, CNRS, UMR LBI2M, Station Biologique de Roscoff SBR, Roscoff, France.,Laboratory of Excellence GR-Ex, Paris, France
| |
Collapse
|
4
|
|
5
|
Cercós P, Peraza DA, de Benito-Bueno A, Socuéllamos PG, Aziz-Nignan A, Arrechaga-Estévez D, Beato E, Peña-Acevedo E, Albert A, González-Vera JA, Rodríguez Y, Martín-Martínez M, Valenzuela C, Gutiérrez-Rodríguez M. Pharmacological Approaches for the Modulation of the Potassium Channel K V4.x and KChIPs. Int J Mol Sci 2021; 22:ijms22031419. [PMID: 33572566 PMCID: PMC7866805 DOI: 10.3390/ijms22031419] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 02/06/2023] Open
Abstract
Ion channels are macromolecular complexes present in the plasma membrane and intracellular organelles of cells. Dysfunction of ion channels results in a group of disorders named channelopathies, which represent an extraordinary challenge for study and treatment. In this review, we will focus on voltage-gated potassium channels (KV), specifically on the KV4-family. The activation of these channels generates outward currents operating at subthreshold membrane potentials as recorded from myocardial cells (ITO, transient outward current) and from the somata of hippocampal neurons (ISA). In the heart, KV4 dysfunctions are related to Brugada syndrome, atrial fibrillation, hypertrophy, and heart failure. In hippocampus, KV4.x channelopathies are linked to schizophrenia, epilepsy, and Alzheimer's disease. KV4.x channels need to assemble with other accessory subunits (β) to fully reproduce the ITO and ISA currents. β Subunits affect channel gating and/or the traffic to the plasma membrane, and their dysfunctions may influence channel pharmacology. Among KV4 regulatory subunits, this review aims to analyze the KV4/KChIPs interaction and the effect of small molecule KChIP ligands in the A-type currents generated by the modulation of the KV4/KChIP channel complex. Knowledge gained from structural and functional studies using activators or inhibitors of the potassium current mediated by KV4/KChIPs will better help understand the underlying mechanism involving KV4-mediated-channelopathies, establishing the foundations for drug discovery, and hence their treatments.
Collapse
Affiliation(s)
- Pilar Cercós
- Instituto de Química Médica (IQM-CSIC), 28006 Madrid, Spain; (P.C.); (M.M.-M.)
| | - Diego A. Peraza
- Instituto de Investigaciones Biomédicas Alberto Sols (IIBM), CSIC-UAM, 28029 Madrid, Spain; (D.A.P.); (A.d.B.-B.); (P.G.S.)
- Spanish Network for Biomedical Research in Cardiovascular Research (CIBERCV), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Angela de Benito-Bueno
- Instituto de Investigaciones Biomédicas Alberto Sols (IIBM), CSIC-UAM, 28029 Madrid, Spain; (D.A.P.); (A.d.B.-B.); (P.G.S.)
- Spanish Network for Biomedical Research in Cardiovascular Research (CIBERCV), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Paula G. Socuéllamos
- Instituto de Investigaciones Biomédicas Alberto Sols (IIBM), CSIC-UAM, 28029 Madrid, Spain; (D.A.P.); (A.d.B.-B.); (P.G.S.)
- Spanish Network for Biomedical Research in Cardiovascular Research (CIBERCV), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Abdoul Aziz-Nignan
- Department of Natural Sciences, Hostos Community College of CUNY, New York, NY 10451, USA; (A.A.-N.); (D.A.-E.); (E.B.); (E.P.-A.); (Y.R.)
| | - Dariel Arrechaga-Estévez
- Department of Natural Sciences, Hostos Community College of CUNY, New York, NY 10451, USA; (A.A.-N.); (D.A.-E.); (E.B.); (E.P.-A.); (Y.R.)
| | - Escarle Beato
- Department of Natural Sciences, Hostos Community College of CUNY, New York, NY 10451, USA; (A.A.-N.); (D.A.-E.); (E.B.); (E.P.-A.); (Y.R.)
| | - Emilio Peña-Acevedo
- Department of Natural Sciences, Hostos Community College of CUNY, New York, NY 10451, USA; (A.A.-N.); (D.A.-E.); (E.B.); (E.P.-A.); (Y.R.)
| | - Armando Albert
- Instituto de Química Física Rocasolano (IQFR-CSIC), 28006 Madrid, Spain;
| | - Juan A. González-Vera
- Departamento de Físicoquímica, Facultad de Farmacia, Universidad de Granada, 18071 Granada, Spain;
| | - Yoel Rodríguez
- Department of Natural Sciences, Hostos Community College of CUNY, New York, NY 10451, USA; (A.A.-N.); (D.A.-E.); (E.B.); (E.P.-A.); (Y.R.)
| | | | - Carmen Valenzuela
- Instituto de Investigaciones Biomédicas Alberto Sols (IIBM), CSIC-UAM, 28029 Madrid, Spain; (D.A.P.); (A.d.B.-B.); (P.G.S.)
- Spanish Network for Biomedical Research in Cardiovascular Research (CIBERCV), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence: ; (C.V.); (M.G.-R.); Tel.: +34-91-585-4493 (C.V.); +34-91-258-7493 (M.-G.R.)
| | - Marta Gutiérrez-Rodríguez
- Instituto de Química Médica (IQM-CSIC), 28006 Madrid, Spain; (P.C.); (M.M.-M.)
- Correspondence: ; (C.V.); (M.G.-R.); Tel.: +34-91-585-4493 (C.V.); +34-91-258-7493 (M.-G.R.)
| |
Collapse
|
6
|
Shah F, Dwivedi M. Pathophysiology and recent therapeutic insights of sickle cell disease. Ann Hematol 2020; 99:925-935. [PMID: 32157419 DOI: 10.1007/s00277-020-03977-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Accepted: 02/25/2020] [Indexed: 02/07/2023]
Abstract
Sickle cell disease (SCD) is an autosomal recessive blood disorder which occurs due to point mutation in the β-globin chain of hemoglobin. Since the past decades, various therapies have been put forth, which are based on obstructing pathophysiological mechanisms of SCD including inhibition of Gardos channel and cation fluxes which in turn prevents sickle erythrocyte destruction and dehydration. The pharmacological approaches are based on the mechanism of reactivating γ-globin expression by utilizing fetal hemoglobin (HbF)-inducing drugs such as hydroxyurea. In SCD, gene therapy could be considered as a promising tool which involves modifying mutation at the gene-specific target by either promoting insertion or deletion of globins. Although there are various therapies emerged so far in the treatment of SCD, many of them have faced a major setback in most of developing countries in terms of cost, unavailability of expertise, and suitable donor. Therefore, in addition to pathophysiological aspects, this review will discuss new advancements and approaches made in the therapeutic domain of SCD including a viewpoint of modulating hemoglobin in SCD by the intervention of probiotics.
Collapse
Affiliation(s)
- Firdosh Shah
- C. G. Bhakta Institute of Biotechnology, Faculty of Science, Uka Tarsadia University, Maliba Campus, Gopal Vidyanagar, Bardoli-Mahuva Road, Dist. Surat, Tarsadi, Bardoli, Gujarat, 394350, India
| | - Mitesh Dwivedi
- C. G. Bhakta Institute of Biotechnology, Faculty of Science, Uka Tarsadia University, Maliba Campus, Gopal Vidyanagar, Bardoli-Mahuva Road, Dist. Surat, Tarsadi, Bardoli, Gujarat, 394350, India.
| |
Collapse
|
7
|
Impact of a 10 km running trial on eryptosis, red blood cell rheology, and electrophysiology in endurance trained athletes: a pilot study. Eur J Appl Physiol 2019; 120:255-266. [PMID: 31776697 DOI: 10.1007/s00421-019-04271-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 11/22/2019] [Indexed: 02/06/2023]
Abstract
PURPOSE Blood rheology is a key determinant of blood flow and tissue perfusion. There are still large discrepancies regarding the effects of an acute running exercise on blood rheological properties and red blood cell (RBC) physiology. We investigated the effect of a 10 km running trial on markers of blood rheology and RBC physiology in endurance trained athletes. METHODS Blood was sampled before and after the exercise to measure lactate and glucose, hematological and hemorheological parameters (blood viscosity, RBC deformability, and aggregation), eryptosis markers (phosphatidylserine and CD47 exposure, RBC reactive oxygen species), RBC-derived microparticles (RBC-MPs), and RBC electrophysiological activity. Weight was measured before and after exercise. Peripheral oxygen saturation and heart rate were monitored before and during the trial. RESULTS Blood lactate and glucose levels increased after exercise and subjects significantly lost weight. All athletes experienced a significant fall in oxygen saturation. Mean corpuscular volume (MCV) was increased from 95.1 ± 3.2 to 96.0 ± 3.3 and mean corpuscular hemoglobin concentration (MCHC) decreased after exercise suggesting a slight RBC rehydration. Exercise increased RBC deformability from 0.344 ± 0.04 to 0.378 ± 0.07, decreased RBC aggregates strength and blood viscosity, while hematocrit (Hct) remained unaffected. While RBC electrophysiological recording suggested a modulation in RBC calcium content and/or chloride conductance, eryptosis markers and RBC-MPs were not modified by the exercise. CONCLUSION A 10 km acute running exercise had no effect on RBC senescence and membrane blebbing. In contrast, this exercise increased RBC deformability, probably through rehydration process which resulted in a decrease in blood viscosity.
Collapse
|
8
|
Abstract
BACKGROUND Sickle cell disease is an autosomal recessive inherited haemoglobinopathy which causes painful vaso-occlusive crises due to sickle red blood cell dehydration. Vaso-occlusive crises are common painful events responsible for a variety of clinical complications; overall mortality is increased and life expectancy decreased compared to the general population. Experimental studies suggest that intravenous magnesium has proven to be well-tolerated in individuals hospitalised for the immediate relief of acute (sudden onset) painful crisis and has the potential to decrease the length of hospital stay. Some in vitro studies and open studies of long-term oral magnesium showed promising effect on pain relief but failed to show its efficacy. The studies show that oral magnesium therapy may prevent sickle red blood cell dehydration and prevent recurrent painful episodes. There is a need to access evidence for the impact of oral and intravenous magnesium effect on frequency of pain, length of hospital stay and quality of life. This is an updated version of the review. OBJECTIVES To evaluate the effects of short-term intravenous magnesium on the length of hospital stay and quality of life in children and adults with sickle cell disease. To determine the effects of long-term oral magnesium therapy on the frequency of painful crises and the quality of life in children and adults with sickle cell disease. SEARCH METHODS We searched the Cochrane Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books.Date of last search of the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register: 03 February 2019.Date of last search of other resources (clinical trials registries): 04 April 2019. SELECTION CRITERIA We searched for published and unpublished randomized controlled studies of oral or intravenous magnesium compared to placebo or no magnesium. DATA COLLECTION AND ANALYSIS Authors independently assessed the study quality and extracted the data using standard Cochrane methodologies. MAIN RESULTS We included five randomized placebo-controlled studies with a total of 386 participants (aged three to 53 years). Of these, two shorter parallel studies (n = 306) compared intravenous magnesium sulphate to placebo (normal saline) for admission to hospital due to a vaso-occlusive crisis, for which we were able to analyse data. The quality of evidence was moderate for studies in this comparison, mainly due to limitations due to risk of bias and imprecision. Two of the three longer-term studies comparing oral magnesium pidolate to placebo had a cross-over design. The third was a parallel factorial study which compared hydroxyurea and oral magnesium to each other and to placebo over a longer period of time; we only present the comparison of oral magnesium to placebo from this study. The quality of evidence was very low with uncertainty of the estimation.The eight-hourly dose levels in the two studies of intravenous magnesium were different; one used 100 mg/kg while the second used 40 mg/kg. Only one of these studies (n = 104) reported the mean daily pain score while hospitalised (a non-significant difference between groups, moderate quality evidence). The second study (n = 202) reported a number of child- and parent-reported quality of life scores. None of the scores showed any difference between treatment groups (low quality evidence). Data from one study (n = 106) showed no difference in length of stay in hospital between groups (low quality evidence). Both studies reported on adverse events, but not defined by severity as we had planned. One study showed significantly more participants receiving intravenous magnesium experienced warmth at infusion site compared to placebo; there were no differences between groups for other adverse events (low quality evidence).Three studies (n = 80) compared oral magnesium pidolate to placebo. None of them reported data which we were able to analyse. One study (n = 24) reported on the number of painful days and stated there was no difference between two groups (low quality evidence). None of the studies reported on quality of life or length of hospital stay. Two studies (n = 68) reported there were no differences in levels of magnesium in either plasma or red blood cells (moderate quality evidence). Two studies (n = 56) reported adverse events. One reported episodes of mild diarrhoea and headache, all of which resolved without stopping treatment. The second study reported adverse events as gastrointestinal disorders, headache or migraine, upper respiratory infections and rash; which were all evenly distributed across treatment groups (moderate quality evidence). AUTHORS' CONCLUSIONS Moderate to low quality evidence showed neither intravenous magnesium and oral magnesium therapy has an effect on reducing painful crisis, length of hospital stay and changing quality of life in treating sickle cell disease. Therefore, no definitive conclusions can be made regarding its clinical benefit. Further randomized controlled studies, perhaps multicentre, are necessary to establish whether intravenous and oral magnesium therapies have any effect on improving the health of people with sickle cell disease.
Collapse
Affiliation(s)
- Nan Nitra Than
- Faculty of Medicine, Melaka‐Manipal Medical College (MMMC), Manipal Academy of Higher Education(MAHE)Department of Community MedicineMelakaMalaysia75150
| | - Htoo Htoo Kyaw Soe
- Faculty of Medicine, Melaka‐Manipal Medical College, Manipal Academy of Higher Education (MAHE)Department of Community MedicineJalan Batu HamparBukit BaruMelakaMalaysia75150
| | - Senthil K Palaniappan
- NHS trustDepartment of Medicine, University Hospitals of LeicesterLeicester Royal InfirmaryLeicesterUKLE1 5WW
| | - Adinegara BL Abas
- Melaka‐Manipal Medical College (Manipal Academy of Higher Education)Department of Community MedicineJalan Batu HamparBukit BaruMelakaMalaysia75150
| | - Lucia De Franceschi
- University of Verona‐AOUI VeronaDepartment of MedicinePolilinico GB RossiVeronaItaly37134
| | | |
Collapse
|
9
|
Calloe K. Doctoral Dissertation: The transient outward potassium current in healthy and diseased hearts. Acta Physiol (Oxf) 2019; 225 Suppl 717:e13225. [PMID: 30628199 DOI: 10.1111/apha.13225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 11/20/2018] [Accepted: 11/21/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Kirstine Calloe
- Section for Anatomy; Biochemistry and Physiology; Department for Veterinary and Animal Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Frederiksberg C Denmark
| |
Collapse
|
10
|
Nagalla S, Ballas SK. Drugs for preventing red blood cell dehydration in people with sickle cell disease. Cochrane Database Syst Rev 2018; 10:CD003426. [PMID: 30338520 PMCID: PMC6517013 DOI: 10.1002/14651858.cd003426.pub6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs. This is an updated version of a previously published review. OBJECTIVES To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells. SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register. We also searched online trials registries for any ongoing trials (01 July 2018).Last search of the Group's Haemoglobinopathies Trials Register: 08 October 2018. SELECTION CRITERIA Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment. DATA COLLECTION AND ANALYSIS Both authors independently selected studies for inclusion, assessed study quality and extracted data. MAIN RESULTS Of the 51 studies identified, three met the inclusion criteria, including 524 people with sickle cell disease aged between 12 and 65 years of age. One study tested the effectiveness of zinc sulphate as compared to placebo and the remaining two assessed senicapoc versus placebo. No deaths were seen in any of the studies (low-quality evidence). The zinc sulphate study showed a significant reduction in painful crises (in a total of 145 participants) over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15) (moderate-quality evidence). However, analysis was restricted due to limited statistical data. Changes to red blood cell parameters and blood counts were inconsistent (very low-quality evidence). No serious adverse events were noted in the study. The Phase II dose-finding study of senicapoc (a Gardos channel blocker) compared to placebo showed that the high dose senicapoc showed significant improvement in change in hemoglobin level, the number and proportion of dense red blood cells, red blood cell count and indices and hematocrit value (very low-quality evidence). The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups (low-quality evidence). A subsequent Phase III study of senicapoc was terminated early since there was no difference observed between the treatment and control groups in the primary end point of painful crises. AUTHORS' CONCLUSIONS While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicenter studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.While the Phase II and the prematurely terminated phase III studies of senicapoc showed that the drug improved red blood cell survival (depending on dose), this did not lead to fewer painful crises.Given this is no longer an active area of research, this review will no longer be regularly updated.
Collapse
Affiliation(s)
- Srikanth Nagalla
- Division of Hematology and Oncology, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas, USA, 75390
| | | |
Collapse
|
11
|
Lainez S, Doray A, Hancox JC, Cannell MB. Regulation of Kv4.3 and hERG potassium channels by KChIP2 isoforms and DPP6 and response to the dual K + channel activator NS3623. Biochem Pharmacol 2018; 150:120-130. [PMID: 29378180 PMCID: PMC5906734 DOI: 10.1016/j.bcp.2018.01.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 01/22/2018] [Indexed: 12/14/2022]
Abstract
Transient outward potassium current (Ito) contributes to early repolarization of many mammalian cardiac action potentials, including human, whilst the rapid delayed rectifier K+ current (IKr) contributes to later repolarization. Fast Ito channels can be produced from the Shal family KCNDE gene product Kv4.3s, although accessory subunits including KChIP2.x and DPP6 are also needed to produce a near physiological Ito. In this study, the effect of KChIP2.1 & KChIP2.2 (also known as KChIP2b and KChIP2c respectively), alone or in conjunction with the accessory subunit DPP6, on both Kv4.3 and hERG were evaluated. A dual Ito and IKr activator, NS3623, has been recently proposed to be beneficial in heart failure and the action of NS3623 on the two channels was also investigated. Whole-cell patch-clamp experiments were performed at 33 ± 1 °C on HEK293 cells expressing Kv4.3 or hERG in the absence or presence of these accessory subunits. Kv4.3 current magnitude was augmented by co-expression with either KChIP2.2 or KChIP2.1 and KChIP2/DPP6 with KChIP2.1 producing a greater effect than KChIP2.2. Adding DPP6 removed the difference in Kv4.3 augmentation between KChIP2.1 and KChIP2.2. The inactivation rate and recovery from inactivation were also altered by KChIP2 isoform co-expression. In contrast, hERG (Kv11.1) current was not altered by co-expression with KChIP2.1, KChIP2.2 or DPP6. NS3623 increased Kv4.3 amplitude to a similar extent with and without accessory subunit co-expression, however KChIP2 isoforms modulated the compound’s effect on inactivation time course. The agonist effect of NS3623 on hERG channels was not affected by KChIP2.1, KChIP2.2 or DPP6 co-expression.
Collapse
Affiliation(s)
- Sergio Lainez
- School of Physiology, Pharmacology and Neuroscience, Faculty of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Adélaïde Doray
- School of Physiology, Pharmacology and Neuroscience, Faculty of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Jules C Hancox
- School of Physiology, Pharmacology and Neuroscience, Faculty of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK.
| | - Mark B Cannell
- School of Physiology, Pharmacology and Neuroscience, Faculty of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK.
| |
Collapse
|
12
|
Abstract
Cell dehydration is a distinguishing characteristic of sickle cell disease and an important contributor to disease pathophysiology. Due to the unique dependence of Hb S polymerization on cellular Hb S concentration, cell dehydration promotes polymerization and sickling. In double heterozygosis for Hb S and C (SC disease) dehydration is the determining factor in disease pathophysiology. Three major ion transport pathways are involved in sickle cell dehydration: the K-Cl cotransport (KCC), the Gardos channel (KCNN4) and Psickle, the polymerization induced membrane permeability, most likely mediated by the mechano-sensitive ion channel PIEZO1. Each of these pathways exhibit unique characteristics in regulation by oxygen tension, intracellular and extracellular environment, and functional expression in reticulocytes and mature red cells. The unique dependence of K-Cl cotransport on intracellular Mg and the abnormal reduction of erythrocyte Mg content in SS and SC cells had led to clinical studies assessing the effect of oral Mg supplementation. Inhibition of Gardos channel by clotrimazole and senicapoc has led to Phase 1,2,3 trials in patients with sickle cell disease. While none of these studies has resulted in the approval of a novel therapy for SS disease, they have highlighted the key role played by these pathways in disease pathophysiology.
Collapse
Affiliation(s)
- Carlo Brugnara
- Department of Laboratory Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
13
|
Abstract
BACKGROUND Sickle cell disease is an autosomal recessive inherited haemoglobinopathy which causes painful vaso-occlusive crises due to sickle red blood cell dehydration. Vaso-occlusive crises are common painful events responsible for a variety of clinical complications; overall mortality is increased and life expectancy decreased compared to the general population. Experimental studies suggest that intravenous magnesium has proven to be well-tolerated in individuals hospitalised for the immediate relief of acute (sudden onset) painful crisis and has the potential to decrease the length of hospital stay. Some in vitro studies and open studies of long-term oral magnesium showed promising effect on pain relief but failed to show its efficacy. The studies show that oral magnesium therapy may prevent sickle red blood cell dehydration and prevent recurrent painful episodes. There is a need to access evidence for the impact of oral and intravenous magnesium effect on frequency of pain, length of hospital stay and quality of life. OBJECTIVES To evaluate the effects of short-term intravenous magnesium on the length of hospital stay and quality of life in children and adults with sickle cell disease. To determine the effects of long-term oral magnesium therapy on the frequency of painful crises and the quality of life in children and adults with sickle cell disease. SEARCH METHODS We searched the Cochrane Haemoglobinopathies Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books.Date of last search of the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register: 01 December 2016.Date of last search of other resources (clinical trials registries): 29 March 2017. SELECTION CRITERIA We searched for published and unpublished randomized controlled studies of oral or intravenous magnesium compared to placebo or no magnesium. DATA COLLECTION AND ANALYSIS Authors independently assessed the study quality and extracted the data using standard Cochrane methodologies. MAIN RESULTS We included five randomized placebo-controlled studies with a total of 386 participants (aged three to 53 years). Two shorter parallel studies (n = 306) compared intravenous magnesium sulphate to placebo (normal saline) for admission to hospital due to a vaso-occlusive crisis, for which we were able to analyse data. The quality of evidence was moderate for studies presenting this comparison mainly due to limitations due to risk of bias and imprecision. Two of the three longer-term studies comparing oral magnesium pidolate to placebo had a cross-over design. The third was a parallel factorial study which compared hydroxyurea and oral magnesium to each other and to placebo over a longer period of time; we only present the comparison of oral magnesium to placebo from this study. The quality of evidence was very low with uncertainty of the estimation.The eight-hourly dose levels in the two studies of intravenous magnesium were different; one used 100 mg/kg while the second used 40 mg/kg. Only one of these studies (n = 104) reported the mean daily pain score while hospitalised (a non-significant difference between groups, moderate quality evidence). The second study (n = 202) reported a number of child- and parent-reported quality of life scores. None of the scores showed any difference between treatment groups (low quality evidence). Data from one study (n = 106) showed no difference in length of stay in hospital between groups (low quality evidence). Both studies reported on adverse events, but not defined by severity as we had planned. One study showed significantly more participants receiving intravenous magnesium experienced warmth at infusion site compared to placebo; there were no differences between groups for other adverse events (low quality evidence).Three studies (n = 80) compared oral magnesium pidolate to placebo. None of them reported data which we were able to analyse. One study (n = 24) reported on the number of painful days and stated there was no difference between two groups (low quality evidence). None of the studies reported on quality of life or length of hospital stay. Two studies (n = 68) reported there were no differences in levels of magnesium in either plasma or red blood cells (moderate quality evidence). Two studies (n = 56) reported adverse events. One reported episodes of mild diarrhoea and headache, all of which resolved without stopping treatment. The second study reported adverse events as gastrointestinal disorders, headache or migraine, upper respiratory infections and rash; which were all evenly distributed across treatment groups (moderate quality evidence). AUTHORS' CONCLUSIONS Moderate to low quality evidence showed neither intravenous magnesium and oral magnesium therapy has an effect on reducing painful crisis, length of hospital stay and changing quality of life in treating sickle cell disease. Therefore, no definitive conclusions can be made regarding its clinical benefit. Further randomized controlled studies, perhaps multicentre, are necessary to establish whether intravenous and oral magnesium therapies have any effect on improving the health of people with sickle cell disease.
Collapse
Affiliation(s)
- Nan Nitra Than
- Melaka‐Manipal Medical CollegeDepartment of Community MedicineJalan Batu HamparBukit BaruMelakaMalaysia75150
| | - Htoo Htoo Kyaw Soe
- Melaka‐Manipal Medical CollegeDepartment of Community MedicineJalan Batu HamparBukit BaruMelakaMalaysia75150
| | - Senthil K Palaniappan
- NHS trustDepartment of Medicine, University Hospitals of LeicesterLeicester Royal InfirmaryLeicesterUKLE1 5WW
| | - Adinegara BL Abas
- Melaka‐Manipal Medical CollegeDepartment of Community MedicineJalan Batu HamparBukit BaruMelakaMalaysia75150
| | - Lucia De Franceschi
- University of Verona‐AOUI VeronaDepartment of MedicinePolilinico GB RossiVeronaItaly37134
| |
Collapse
|
14
|
Nagalla S, Ballas SK. Drugs for preventing red blood cell dehydration in people with sickle cell disease. Cochrane Database Syst Rev 2016; 3:CD003426. [PMID: 26942338 DOI: 10.1002/14651858.cd003426.pub5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs. This is an updated version of a previously published review. OBJECTIVES To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells. SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register.Last search of the Group's Trials Register: 28 November 2015. SELECTION CRITERIA Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment. DATA COLLECTION AND ANALYSIS Both authors independently selected studies for inclusion, assessed study quality and extracted data. MAIN RESULTS Of the 51 studies identified, three met the inclusion criteria. The first study tested the effectiveness of zinc sulphate to prevent sickle cell-related crises in a total of 145 participants and showed a significant reduction in painful crises over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15). However, analysis was restricted due to limited statistical data. Changes to red cell parameters and blood counts were inconsistent. No serious adverse events were noted in the study.The second study was a Phase II dose-finding study of senicapoc (a Gardos channel blocker) compared to placebo. Compared to the placebo group the high dose senicapoc showed significant improvement in change in hemoglobin level, number and proportion of dense red blood cells, red blood cell count and indices and hematocrit. The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups. A subsequent Phase III study of senicapoc was terminated early since there was no difference observed between the treatment and control groups in the primary end point of painful crises. AUTHORS' CONCLUSIONS While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicenter studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.While the Phase II and the prematurely terminated phase III studies of senicapoc showed that the drug improved red cell survival (depending on dose), this did not lead to fewer painful crises.We will continue to run searches to identify any potentially relevant trials; however, we do not plan to update other sections of the review until new trials are published.
Collapse
Affiliation(s)
- Srikanth Nagalla
- Department of Medicine, Division of Hematology, Thomas Jefferson University, Medical Center Boulevard, 1015 Walnut Street, Philadelphia, Pennsylvania, USA, PA 19107-5099
| | | |
Collapse
|
15
|
King MA, Clanton TL, Laitano O. Hyperthermia, dehydration, and osmotic stress: unconventional sources of exercise-induced reactive oxygen species. Am J Physiol Regul Integr Comp Physiol 2016; 310:R105-14. [DOI: 10.1152/ajpregu.00395.2015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 11/10/2015] [Indexed: 12/17/2022]
Abstract
Evidence of increased reactive oxygen species (ROS) production is observed in the circulation during exercise in humans. This is exacerbated at elevated body temperatures and attenuated when normal exercise-induced body temperature elevations are suppressed. Why ROS production during exercise is temperature dependent is entirely unknown. This review covers the human exercise studies to date that provide evidence that oxidant and antioxidant changes observed in the blood during exercise are dependent on temperature and fluid balance. We then address possible mechanisms linking exercise with these variables that include shear stress, effects of hemoconcentration, and signaling pathways involving muscle osmoregulation. Since pathways of muscle osmoregulation are rarely discussed in this context, we provide a brief review of what is currently known and unknown about muscle osmoregulation and how it may be linked to oxidant production in exercise and hyperthermia. Both the circulation and the exercising muscle fibers become concentrated with osmolytes during exercise in the heat, resulting in a competition for available water across the muscle sarcolemma and other tissues. We conclude that though multiple mechanisms may be responsible for the changes in oxidant/antioxidant balance in the blood during exercise, a strong case can be made that a significant component of ROS produced during some forms of exercise reflect requirements of adapting to osmotic challenges, hyperthermia challenges, and loss of circulating fluid volume.
Collapse
Affiliation(s)
| | | | - Orlando Laitano
- University of Florida, Applied Physiology and Kinesiology, and
- Universidade Federal do Vale do São Francisco, Colegiado de Educação Física, Brazil
| |
Collapse
|
16
|
Nakagawa A, Lui FE, Wassaf D, Yefidoff-Freedman R, Casalena D, Palmer MA, Meadows J, Mozzarelli A, Ronda L, Abdulmalik O, Bloch KD, Safo MK, Zapol WM. Identification of a small molecule that increases hemoglobin oxygen affinity and reduces SS erythrocyte sickling. ACS Chem Biol 2014; 9:2318-25. [PMID: 25061917 PMCID: PMC4205001 DOI: 10.1021/cb500230b] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Small
molecules that increase the oxygen affinity of human hemoglobin
may reduce sickling of red blood cells in patients with sickle cell
disease. We screened 38 700 compounds using small molecule
microarrays and identified 427 molecules that bind to hemoglobin.
We developed a high-throughput assay for evaluating the ability of
the 427 small molecules to modulate the oxygen affinity of hemoglobin.
We identified a novel allosteric effector of hemoglobin, di(5-(2,3-dihydro-1,4-benzodioxin-2-yl)-4H-1,2,4-triazol-3-yl)disulfide
(TD-1). TD-1 induced a greater increase in oxygen affinity of human
hemoglobin in solution and in red blood cells than did 5-hydroxymethyl-2-furfural
(5-HMF), N-ethylmaleimide (NEM), or diformamidine disulfide. The three-dimensional
structure of hemoglobin complexed with TD-1 revealed that monomeric
units of TD-1 bound covalently to β-Cys93 and β-Cys112,
as well as noncovalently to the central water cavity of the hemoglobin
tetramer. The binding of TD-1 to hemoglobin stabilized the relaxed
state (R3-state) of hemoglobin. TD-1 increased the oxygen affinity
of sickle hemoglobin and inhibited in vitro hypoxia-induced
sickling of red blood cells in patients with sickle cell disease without
causing hemolysis. Our study indicates that TD-1 represents a novel
lead molecule for the treatment of patients with sickle cell disease.
Collapse
Affiliation(s)
- Akito Nakagawa
- Anesthesia Center
for Critical Care Research, Department of Anesthesia, Critical Care,
and Pain Medicine, Massachusetts General Hospital and Harvard Medical
School, 55 Fruit Street, Boston, Massachusetts 02114, United States
| | - Francine E. Lui
- Anesthesia Center
for Critical Care Research, Department of Anesthesia, Critical Care,
and Pain Medicine, Massachusetts General Hospital and Harvard Medical
School, 55 Fruit Street, Boston, Massachusetts 02114, United States
| | - Dina Wassaf
- The Broad Institute
of MIT and Harvard, Chemical Biology Platform, 7 Cambridge Center, Cambridge, Massachusetts 02142, United States
| | - Revital Yefidoff-Freedman
- Anesthesia Center
for Critical Care Research, Department of Anesthesia, Critical Care,
and Pain Medicine, Massachusetts General Hospital and Harvard Medical
School, 55 Fruit Street, Boston, Massachusetts 02114, United States
| | - Dominick Casalena
- The Broad Institute
of MIT and Harvard, Chemical Biology Platform, 7 Cambridge Center, Cambridge, Massachusetts 02142, United States
| | - Michelle A. Palmer
- The Broad Institute
of MIT and Harvard, Chemical Biology Platform, 7 Cambridge Center, Cambridge, Massachusetts 02142, United States
| | - Jacqueline Meadows
- Department
of Medicinal Chemistry, Institute for Structural Biology and Drug
Discovery, School of Pharmacy, Virginia Commonwealth University, 800 East Leigh Street, Richmond, Virginia 23219, United States
| | - Andrea Mozzarelli
- Department
of Pharmacy, University of Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy
| | - Luca Ronda
- Department
of Neuroscience, University of Parma, Parco Area delle Scienze 23/A, 43124 Parma, Italy
| | - Osheiza Abdulmalik
- Division of Hematology,
The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, United States
| | - Kenneth D. Bloch
- Anesthesia Center
for Critical Care Research, Department of Anesthesia, Critical Care,
and Pain Medicine, Massachusetts General Hospital and Harvard Medical
School, 55 Fruit Street, Boston, Massachusetts 02114, United States
| | - Martin K. Safo
- Department
of Medicinal Chemistry, Institute for Structural Biology and Drug
Discovery, School of Pharmacy, Virginia Commonwealth University, 800 East Leigh Street, Richmond, Virginia 23219, United States
| | - Warren M. Zapol
- Anesthesia Center
for Critical Care Research, Department of Anesthesia, Critical Care,
and Pain Medicine, Massachusetts General Hospital and Harvard Medical
School, 55 Fruit Street, Boston, Massachusetts 02114, United States
| |
Collapse
|
17
|
Swe KMM, Abas ABL, Bhardwaj A, Barua A, Nair NS. Zinc supplements for treating thalassaemia and sickle cell disease. Cochrane Database Syst Rev 2013; 2013:CD009415. [PMID: 23807756 PMCID: PMC9964104 DOI: 10.1002/14651858.cd009415.pub2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Haemoglobinopathies, inherited disorders of haemoglobin synthesis (thalassaemia) or structure (sickle cell disease), are responsible for significant morbidity and mortality throughout the world. The WHO estimates that, globally, 5% of adults are carriers of a haemoglobin condition, 2.9% are carriers of thalassaemia and 2.3% are carriers of sickle cell disease. Carriers are found worldwide as a result of migration of various ethnic groups to different regions of the world. Zinc is an easily available supplement and intervention programs have been carried out to prevent deficiency in people with thalassaemia or sickle cell anaemia. It is important to evaluate the role of zinc supplementation in the treatment of thalassaemia and sickle cell anaemia to reduce deaths due to complications. OBJECTIVES To assess the effect of zinc supplementation in the treatment of thalassaemia and sickle cell disease. SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Date of most recent search: 01 February 2013. SELECTION CRITERIA Randomised, placebo-controlled trials of zinc supplements for treating thalassaemia or sickle cell disease administered at least once a week for at least a month. DATA COLLECTION AND ANALYSIS Two review authors assessed the eligibility and risk of bias of the included trials, extracted and analysed data and wrote the review. We summarised results using risk ratios or rate ratios for dichotomous data and mean differences for continuous data. We combined trial results where appropriate. MAIN RESULTS We identified nine trials for inclusion with all nine contributing outcome data. Two trials reported on people with thalassaemia (n = 152) and seven on sickle cell anaemia (n = 307).In people with thalassaemia, in one trial, the serum zinc level value showed no difference between the zinc supplemented group and the control group, mean difference 47.40 (95% confidence interval -12.95 to 107.99). Regarding anthropometry, in one trial, height velocity was significantly increased in patients who received zinc supplementation for one to seven years duration, mean difference 3.37 (95% confidence interval 2.36 to 4.38) (total number of participants = 26). In one trial, however, there was no difference in body mass index between treatment groups.Zinc acetate supplementation for three months (in one trial) and one year (in two trials) (total number of participants = 71) was noted to increase the serum zinc level significantly in patients with sickle cell anaemia, mean difference 14.90 (95% confidence interval 6.94 to 22.86) and 20.25 (95% confidence interval 11.73 to 28.77) respectively. There was no significant difference in haemoglobin level between intervention and control groups, at either three months (one trial) or one year (one trial), mean difference 0.06 (95% confidence interval -0.84 to 0.96) and mean difference -0.07 (95% confidence interval -1.40 to 1.26) respectively. Regarding anthropometry, one trial showed no significant changes in body mass index or weight after one year of zinc acetate supplementation. In patients with sickle cell disease, the total number of sickle cell crises at one year were significantly decreased in the zinc sulphate supplemented group as compared to controls, mean difference -2.83 (95% confidence interval -3.51 to -2.15) (total participants 130), but not in zinc acetate group, mean difference 1.54 (95% confidence interval -2.01 to 5.09) (total participants 22). In one trial at three months and another at one year, the total number of clinical infections were significantly decreased in the zinc supplemented group as compared to controls, mean difference 0.05 (95% confidence interval 0.01 - 0.43) (total number of participants = 36), and mean difference -7.64 (95% confidence interval -10.89 to -4.39) (total number of participants = 21) respectively. AUTHORS' CONCLUSIONS According to the results, there is no evidence from randomised controlled trials to indicate any benefit of zinc supplementation with regards to serum zinc level in patients with thalassaemia. However, height velocity was noted to increase among those who received this intervention.There is mixed evidence on the benefit of using zinc supplementation in people with sickle cell disease. For instance, there is evidence that zinc supplementation for one year increased the serum zinc levels in patients with sickle cell disease. However, though serum zinc level was raised in patients receiving zinc supplementation, haemoglobin level and anthropometry measurements were not significantly different between groups. Evidence of benefit is seen with the reduction in the number of sickle cell crises among sickle cell patients who received one year of zinc sulphate supplementation and with the reduction in the total number of clinical infections among sickle cell patients who received zinc supplementation for both three months and for one year.The conclusion is based on the data from a small group of trials,which were generally of good quality, with a low risk of bias. The authors recommend that more trials on zinc supplementation in thalassaemia and sickle cell disease be conducted given that the literature has shown the benefits of zinc in these types of diseases.
Collapse
Affiliation(s)
- Kye Mon Min Swe
- Department of Community Medicine, Melaka-Manipal Medical College (MMMC), Melaka, Malaysia.
| | | | | | | | | |
Collapse
|
18
|
Matte A, Bertoldi M, Mohandas N, An X, Bugatti A, Brunati AM, Rusnati M, Tibaldi E, Siciliano A, Turrini F, Perrotta S, De Franceschi L. Membrane association of peroxiredoxin-2 in red cells is mediated by the N-terminal cytoplasmic domain of band 3. Free Radic Biol Med 2013; 55:27-35. [PMID: 23123411 DOI: 10.1016/j.freeradbiomed.2012.10.543] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 09/11/2012] [Accepted: 10/12/2012] [Indexed: 01/31/2023]
Abstract
Band 3 (B3), the anion transporter, is an integral membrane protein that plays a key structural role by anchoring the plasma membrane to the spectrin-based membrane skeleton in the red cell. In addition, it also plays a critical role in the assembly of glycolytic enzymes to regulate red cell metabolism. However, its ability to recruit proteins that can prevent membrane oxidation has not been previously explored. In this study, using a variety of experimental approaches including cross-linking studies, fluorescence and dichroic measurements, surface plasmon resonance analysis, and proteolytic digestion assays, we document that the antioxidant protein peroxiredoxin-2 (PRDX2), the third most abundant cytoplasmic protein in RBCs, interacts with the cytoplasmic domain of B3. The surface electrostatic potential analysis and stoichiometry measurements revealed that the N-terminal peptide of B3 is involved in the interaction. PRDX2 underwent a conformational change upon its binding to B3 without losing its peroxidase activity. Hemichrome formation induced by phenylhydrazine of RBCs prevented membrane association of PRDX2, implying overlapping binding sites. Documentation of the absence of binding of PRDX2 to B3 Neapolis red cell membranes, in which the initial N-terminal 11 amino acids are deleted, enabled us to conclude that PRDX2 binds to the N-terminal cytoplasmic domain of B3 and that the first 11 amino acids of this domain are crucial for PRDX2 membrane association in intact RBCs. These findings imply yet another important role for B3 in regulating red cell membrane function.
Collapse
Affiliation(s)
- Alessandro Matte
- Section of Internal Medicine, Department of Medicine,University of Verona, 37134 Verona, Italy
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
De Franceschi L, Franco RS, Bertoldi M, Brugnara C, Matté A, Siciliano A, Wieschhaus AJ, Chishti AH, Joiner CH. Pharmacological inhibition of calpain-1 prevents red cell dehydration and reduces Gardos channel activity in a mouse model of sickle cell disease. FASEB J 2012; 27:750-9. [PMID: 23085996 DOI: 10.1096/fj.12-217836] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Sickle cell disease (SCD) is a globally distributed hereditary red blood cell (RBC) disorder. One of the hallmarks of SCD is the presence of circulating dense RBCs, which are important in SCD-related clinical manifestations. In human dense sickle cells, we found reduced calpastatin activity and protein expression compared to either healthy RBCs or unfractionated sickle cells, suggesting an imbalance between activator and inhibitor of calpain-1 in favor of activator in dense sickle cells. Calpain-1 is a nonlysosomal cysteine proteinase that modulates multiple cell functions through the selective cleavage of proteins. To investigate the relevance of this observation in vivo, we evaluated the effects of the orally active inhibitor of calpain-1, BDA-410 (30 mg/kg/d), on RBCs from SAD mice, a mouse model for SCD. In SAD mice, BDA-410 improved RBC morphology, reduced RBC density (D(20); from 1106 ± 0.001 to 1100 ± 0.001 g/ml; P<0.05) and increased RBC-K(+) content (from 364 ± 10 to 429 ± 12.3 mmol/kg Hb; P<0.05), markedly reduced the activity of the Ca(2+)-activated K(+)channel (Gardos channel), and decreased membrane association of peroxiredoxin-2. The inhibitory effect of calphostin C, a specific inhibitor of protein kinase C (PKC), on the Gardos channel was eliminated after BDA-410 treatment, which suggests that calpain-1 inhibition affects the PKC-dependent fraction of the Gardos channel. BDA-410 prevented hypoxia-induced RBC dehydration and K(+) loss in SAD mice. These data suggest a potential role of BDA-410 as a novel therapeutic agent for treatment of SCD.
Collapse
|
20
|
Abstract
BACKGROUND Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs. OBJECTIVES To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells. SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register.Last search of the Group's Trials Register: 25 October 2011. SELECTION CRITERIA Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment. DATA COLLECTION AND ANALYSIS Both authors independently selected studies for inclusion, assessed study quality and extracted data. MAIN RESULTS Of the 51 studies identified, three met the inclusion criteria. The first study tested the effectiveness of zinc sulphate to prevent sickle cell-related crises in a total of 145 participants and showed a significant reduction in painful crises over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15). However, analysis was restricted due to limited statistical data. Changes to red cell parameters and blood counts were inconsistent. No serious adverse events were noted in the study.The second study was a Phase II dose-finding study of senicapoc (a Gardos channel blocker) compared to placebo. Compared to the placebo group the high dose senicapoc showed significant improvement in change in hemoglobin level, number and proportion of dense red blood cells, red blood cell count and indices and hematocrit. The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups. A subsequent Phase III study of senicapoc was terminated early since there was no difference observed between the treatment and control groups in the primary end point of painful crises. AUTHORS' CONCLUSIONS While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicenter studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.While the Phase II and the prematurely terminated phase III studies of senicapoc showed that the drug improved red cell survival (depending on dose), this did not lead to fewer painful crises.
Collapse
Affiliation(s)
- Srikanth Nagalla
- Department of Medicine, Division of Hematology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | | |
Collapse
|
21
|
Zhou PZ, Babcock J, Liu LQ, Li M, Gao ZB. Activation of human ether-a-go-go related gene (hERG) potassium channels by small molecules. Acta Pharmacol Sin 2011; 32:781-8. [PMID: 21623390 DOI: 10.1038/aps.2011.70] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Human ether-a-go-go related gene (hERG) potassium (K(+)) channels play a critical role in cardiac action potential repolarization. Mutations that reduce hERG conductance or surface expression may cause congenital long QT syndrome (LQTS). However, the channels can be inhibited by structurally diverse small molecules, resulting in an acquired form of LQTS. Consequently, small molecules that increase the hERG current may be of value for treatment for LQTS. So far, nine hERG activators have been reported. The aim of this review is to discuss recent advances concerning the identification and action mechanism of hERG activators.
Collapse
|
22
|
Effects of disodium cromoglycate on cationic exchange of deoxygenated sickle cells. Eur J Pharmacol 2011; 665:13-8. [PMID: 21586281 DOI: 10.1016/j.ejphar.2011.05.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 05/03/2011] [Indexed: 10/18/2022]
Abstract
In the present work, we explored the way in which cromoglycate, a drug used to treat allergies acts on ion movements in sickle cells. Cells were either slowly deoxygenated by overnight exposure to nitrogen or acutely deoxygenated by exposure to metabisulfite, a strong reducing agent which induces sickling of red blood sickle cells. Flushing the cells with nitrogen increased the intracellular concentration of Na(+) and decreased the intracellular concentration of K(+) and the sum of the concentrations of the two cations. One hundred nM cromoglycate inhibited the decrease of intracellular K(+) and the increase of intracellular Na(+) induced by deoxygenation (n=17). Metabisulfite (100mM) increased the intracellular concentration of Ca(2+) (measured by Fura Red) (n=15) and the shape of the cells (measured by light scattering) (n=9). One μM cromoglycate partially inhibited these two responses. In conclusion, cromoglycate partially inhibits abnormal K(+) loss, Ca(2+) entry pathways or Ca(2+) channels opened by cell deoxygenation and ensuing membrane modifications and prevents cell sickling.
Collapse
|
23
|
Nagalla S, Ballas SK. Drugs for preventing red blood cell dehydration in people with sickle cell disease. Cochrane Database Syst Rev 2010:CD003426. [PMID: 20091545 DOI: 10.1002/14651858.cd003426.pub3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Sickle cell disease is an inherited disorder of hemoglobin, resulting in abnormal red blood cells. These are rigid and may block blood vessels leading to acute painful crises and other complications. Recent research has focused on therapies to rehydrate the sickled cells by reducing the loss of water and ions from them. Little is known about the effectiveness and safety of such drugs. OBJECTIVES To assess the relative risks and benefits of drugs to rehydrate sickled red blood cells. SEARCH STRATEGY We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register.Last search of the Group's Trials Register: 22 May 2009. SELECTION CRITERIA Randomized or quasi-randomized controlled trials of drugs to rehydrate sickled red blood cells compared to placebo or an alternative treatment. DATA COLLECTION AND ANALYSIS Both authors independently selected studies for inclusion, assessed study quality and extracted data. MAIN RESULTS Of the 47 studies identified, two met the inclusion criteria. The first study tested the effectiveness of zinc sulphate to prevent sickle cell-related crises in a total of 145 participants and showed a significant reduction in painful crises over one and a half years, mean difference -2.83 (95% confidence interval -3.51 to -2.15). However, analysis was restricted due to limited statistical data. Changes to red cell parameters and blood counts were inconsistent. No serious adverse events were noted in the study.The second study was a Phase II dose-finding study of senicapoc (Gardos channel blocker) compared to placebo. Compared to the placebo group the high dose senicapoc showed significant improvement in change in hemoglobin level, number and proportion of dense red blood cells, red blood cell count and indices and hematocrit. The results with low-dose senicapoc were similar to the high-dose senicapoc group but of lesser magnitude. There was no difference in the frequency of painful crises between the three groups. A subsequent Phase III study had to be stopped prematurely due to lack of reduction in the number of painful crisis. AUTHORS' CONCLUSIONS While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicentre studies are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.Though the phase II study of senicapoc showed that the drug improved red cell survival, depending on dose, this did not lead to fewer painful crises; a subsequent phase III study was terminated prematurely for this reason.
Collapse
Affiliation(s)
- Srikanth Nagalla
- Division of Hematology & Oncology, Thomas Jefferson University, 1015 Walnut Street, 705 Curtis Building, Philadelphia, USA, PA 19107
| | | |
Collapse
|
24
|
Pantaleo A, De Franceschi L, Ferru E, Vono R, Turrini F. Current knowledge about the functional roles of phosphorylative changes of membrane proteins in normal and diseased red cells. J Proteomics 2009; 73:445-55. [PMID: 19758581 DOI: 10.1016/j.jprot.2009.08.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 07/17/2009] [Accepted: 08/27/2009] [Indexed: 12/20/2022]
Abstract
With the advent of proteomic techniques the number of known post-translational modifications (PTMs) affecting red cell membrane proteins is rapidly growing but the understanding of their role under physiological and pathological conditions is incompletely established. The wide range of hereditary diseases affecting different red cell membrane functions and the membrane modifications induced by malaria parasite intracellular growth represent a unique opportunity to study PTMs in response to variable cellular stresses. In the present review, some of the major areas of interest in red cell membrane research have been considered as modifications of erythrocyte deformability and maintenance of the surface area, membrane transport alterations, and removal of diseased and senescent red cells. In all mentioned research areas the functional roles of PTMs are prevalently restricted to the phosphorylative changes of the more abundant membrane proteins. The insufficient information about the PTMs occurring in a large majority of the red membrane proteins and the general lack of mass spectrometry data evidence the need of new comprehensive, proteomic approaches to improve the understanding of the red cell membrane physiology.
Collapse
Affiliation(s)
- Antonella Pantaleo
- Department of Genetics, Biology and Biochemistry, University of Turin, via Santena 5 bis, 10126 Turin, Italy.
| | | | | | | | | |
Collapse
|
25
|
Conran N, Franco-Penteado CF, Costa FF. Newer aspects of the pathophysiology of sickle cell disease vaso-occlusion. Hemoglobin 2009; 33:1-16. [PMID: 19205968 DOI: 10.1080/03630260802625709] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Sickle cell disease is an inherited disorder of hemoglobin (Hb) synthesis, caused by a single nucleotide substitution (GTG>GAG) at the sixth codon of the beta-globin gene, leading to the production of a defective form of Hb, Hb S. When deoxygenated, Hb S polymerizes, damaging the sickle erythrocyte and it is this polymerization that is the primary indispensable event in the molecular pathogenesis of sickle cell disease. Hb S polymerization results in a series of cellular alterations in red cell morphology and function that shorten the red cell life span and leads to vascular occlusion. Sickle cell disease vaso-occlusion is now known to constitute a complex multifactorial process characterized by recurrent vaso-occlusion, ischemia-reperfusion injury, and oxidative stress with consequent vascular endothelial cell activation that induces a chronic inflammatory state in sickle cell disease individual and is propagated by elevated levels of circulating inflammatory cytokines. Activation of the endothelium results in the induction of endothelial adhesion molecule expression that mediates red and white cell adhesion to the vessel wall and the formation of heterocellular aggregates, followed by secondary red cell trapping, all of which contribute to reduced blood flow and eventually obstruction of the micro-circulation. Reduced nitric oxide bioavailability, caused principally by its consumption by cell-free Hb, liberated during intravascular hemolysis, contributes to this process by facilitating vasoconstriction and adhesion molecule activity.
Collapse
Affiliation(s)
- Nicola Conran
- Hematology and Hemotherapy Center, School of Medical Sciences, UNICAMP, São Paulo, Brazil.
| | | | | |
Collapse
|
26
|
Analysis and monitoring of oxidative stress in exercise and training by FTIR spectrometry. Int J Sports Physiol Perform 2009; 3:119-30. [PMID: 19208921 DOI: 10.1123/ijspp.3.2.119] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
27
|
De Franceschi L, Biondani A, Carta F, Turrini F, Laudanna C, Deana R, Brunati AM, Turretta L, Iolascon A, Perrotta S, Elson A, Bulato C, Brugnara C. PTPepsilon has a critical role in signaling transduction pathways and phosphoprotein network topology in red cells. Proteomics 2008; 8:4695-708. [PMID: 18924107 PMCID: PMC3008556 DOI: 10.1002/pmic.200700596] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Indexed: 12/31/2022]
Abstract
Protein tyrosine phosphatases (PTPs) are crucial components of cellular signal transduction pathways. Here, we report that red blood cells (RBCs) from mice lacking PTPepsilon (Ptpre(-/-)) exhibit (i) abnormal morphology; (ii) increased Ca(2+)-activated-K(+) channel activity, which was partially blocked by the Src family kinases (SFKs) inhibitor PP1; and (iii) market perturbation of the RBC membrane tyrosine (Tyr-) phosphoproteome, indicating an alteration of RBC signal transduction pathways. Using the signaling network computational analysis of the Tyr-phosphoproteomic data, we identified seven topological clusters. We studied cluster 1 containing Fyn, SFK, and Syk another tyrosine kinase. In Ptpre(-/-)mouse RBCs, the activity of Fyn was increased while Syk kinase activity was decreased compared to wild-type RBCs, validating the network computational analysis, and indicating a novel signaling pathway, which involves Fyn and Syk in regulation of red cell morphology.
Collapse
Affiliation(s)
- Lucia De Franceschi
- Department of Clinical and Experimental Medicine, Section of Internal Medicine, University of Verona, Verona, Italy.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Lapaix F, Bouyer G, Thomas S, Egée S. Further characterization of cation channels present in the chicken red blood cell membrane. Bioelectrochemistry 2008; 73:129-36. [PMID: 18534923 DOI: 10.1016/j.bioelechem.2008.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2007] [Revised: 04/04/2008] [Accepted: 04/07/2008] [Indexed: 01/09/2023]
Abstract
In this paper, we provide an update on cation channels in nucleated chicken erythrocytes. Patch-clamp techniques were used to further characterize the two different types of cation channels present in the membrane of chicken red blood. In the whole-cell mode, with Ringer in the bath and internal K+ saline in the pipette solution, the membrane conductance was generated by cationic currents, since the reversal potential was shifted toward cations equilibrium when the impermeant cation NMDG was substituted to small cations. The membrane conductance could be increased by application of mechanical deformation or by the addition of agonists of the cAMP-dependent pathway. At the unitary level, two different types of cationic channels were revealed and could account for the cationic conductance observed in whole-cell configuration. One of them belongs to the family of stretch-activated cationic channel showing changes in activity under conditions of membrane deformation, whereas the second one belongs to the family of the cAMP activated cationic channels. These two channels could be distinguished according to their unitary conductances and drug sensitivities. The stretch-activated channel was sensitive to Gd(3+) and the cAMP-dependent channel was sensitive to flufenamic acid. Possible role of these channels in cell volume regulation process is discussed.
Collapse
Affiliation(s)
- Franck Lapaix
- UMR 7150, Université Pierre and Marie Curie, CNRS Mer et Santé, Station Biologique de Roscoff, Place G. Teissier, Roscoff, France
| | | | | | | |
Collapse
|
29
|
Alper SL, Vandorpe DH, Peters LL, Brugnara C. Reduced DIDS-sensitive chloride conductance in Ae1-/- mouse erythrocytes. Blood Cells Mol Dis 2008; 41:22-34. [PMID: 18329299 DOI: 10.1016/j.bcmd.2008.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Accepted: 01/04/2008] [Indexed: 02/05/2023]
Abstract
The resting membrane potential of the human erythrocyte is largely determined by a constitutive Cl(-) conductance approximately 100-fold greater than the resting cation conductance. The 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS)-sensitive electroneutral Cl(-) transport mediated by the human erythroid Cl(-)/HCO(3)(-) exchanger, AE1 (SLC4A1, band 3) is >10,000-fold greater than can be accounted for by the Cl(-) conductance of the red cell. The molecular identities of conductive anion pathways across the red cell membrane remain poorly defined. We have examined red cell Cl(-) conductance in the Ae1(-/-) mouse as a genetic test of the hypothesis that Ae1 mediates DIDS-sensitive Cl(-) conductance in mouse red cells. We report here that wildtype mouse red cell membrane potential resembles that of human red cells in the predominance of its Cl(-) conductance. We show with four technical approaches that the DIDS-sensitive component of erythroid Cl(-) conductance is reduced or absent from Ae1(-/-) red cells. These results are consistent with the hypothesis that the Ae1 anion exchanger polypeptide can operate infrequently in a conductive mode. However, the fragile red cell membrane of the Ae1(-/-) mouse red cell exhibits reduced abundance or loss of multiple polypeptides. Thus, loss of one or more distinct, DIDS-sensitive anion channel polypeptide(s) from the Ae1(-/-) red cell membrane cannot be ruled out as an explanation for the reduced DIDS-sensitive anion conductance.
Collapse
Affiliation(s)
- Seth L Alper
- Molecular and Vascular Medicine Unit, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
| | | | | | | |
Collapse
|
30
|
Abstract
BACKGROUND Sickle cell disease is an inherited disorder of haemoglobin, which results in abnormal red blood cells. These can deform and cause blockages in blood vessels, leading to acute crises such as pain; stroke and splenic sequestration; and chronic organ and tissue damage. Recently research has begun to focus on therapies which prevent the red blood cells deforming by reducing the loss of water and ions from the cells. However, little is known about the effectiveness and safety of such drugs. OBJECTIVES To assess the relative risks and benefits of drugs which aim to prevent sickle cell-related crises by reducing red blood cell dehydration. SEARCH STRATEGY We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group's Haemoglobinopathies Trials Register which comprises of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. Date of the most recent search of the Group's Haemoglobinopathies Trials Register: November 2006. SELECTION CRITERIA Randomised or quasi-randomised controlled trials of drugs which aim to prevent sickle cell crises by reducing red cell dehydration, compared to placebo or an alternative treatment. DATA COLLECTION AND ANALYSIS Both authors independently selected studies for inclusion, assessed study quality and extracted data from the included studies. MAIN RESULTS Of the 39 studies identified, one met the inclusion criteria. This study tested the effectiveness of zinc sulphate to prevent sickle cell-related crises in a total of 145 participants and showed a significant reduction in the total number of pain, haemolytic, aplastic and sequestration crises over one and a half years, WMD -2.83 (95% CI -3.51 to -2.15). However, our analysis was limited by non-reporting of standard deviations for some data. Changes to red cell parameters and blood counts were inconsistent. No serious adverse events were noted in the study. AUTHORS' CONCLUSIONS While the results of zinc for reducing sickle-related crises are encouraging, larger and longer-term multicentre studies over a number of years are needed to evaluate the effectiveness of this therapy for people with sickle cell disease.
Collapse
|
31
|
Browning JA, Staines HM, Robinson HC, Powell T, Ellory JC, Gibson JS. The effect of deoxygenation on whole-cell conductance of red blood cells from healthy individuals and patients with sickle cell disease. Blood 2007; 109:2622-9. [PMID: 17138828 PMCID: PMC2951509 DOI: 10.1182/blood-2006-03-001404] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2006] [Accepted: 10/23/2006] [Indexed: 11/20/2022] Open
Abstract
Red blood cells from patients with sickle cell disease (SCD) exhibit increased electrogenic cation permeability, particularly following deoxygenation and hemoglobin (Hb) polymerisation. This cation permeability, termed P(sickle), contributes to cellular dehydration and sickling, and its inhibition remains a major goal for SCD treatment. Nevertheless, its characteristics remain poorly defined, its molecular identity is unknown, and effective inhibitors have not been established. Here, patch-clamp methodology was used to record whole-cell currents in single red blood cells from healthy individuals and patients with SCD. Oxygenated normal red blood cells had a low membrane conductance, unaffected by deoxygenation. Oxygenated HbS cells had significantly increased conductance and, on deoxygenation, showed a further rise in membrane conductance. The deoxygenation-induced pathway was variable in magnitude. It had equal permeability to Na(+) and K(+), but was less permeable to NMDG(+) and Cl(-). Conductance to Ca(2+) was also of a similar magnitude to that of monovalent cations. It was inhibited by DIDS (100 microM), Zn(2+) (100 microM), and by Gd(3+) (IC(50) of approximately 2 microM). It therefore shares some properties with P(sickle). These findings represent the first electrical recordings of single HbS cells and will facilitate progress in understanding altered red blood cell cation transport characteristics of SCD.
Collapse
Affiliation(s)
- Joseph A Browning
- Department of Physiology, Anatomy and Genetics, University of Oxford, United Kingdom.
| | | | | | | | | | | |
Collapse
|
32
|
Zifarelli G, Pusch M. CLC chloride channels and transporters: a biophysical and physiological perspective. Rev Physiol Biochem Pharmacol 2007; 158:23-76. [PMID: 17729441 DOI: 10.1007/112_2006_0605] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Chloride-transporting proteins play fundamental roles in many tissues in the plasma membrane as well as in intracellular membranes. They have received increasing attention in the last years because crucial, and often unexpected and novel, physiological functions have been disclosed with gene-targeting approaches, X-ray crystallography, and biophysical analysis. CLC proteins form a gene family that comprises nine members in mammals, at least four of which are involved in human genetic diseases. The X-ray structure of the bacterial CLC homolog, ClC-ec1, revealed a complex fold and confirmed the anticipated homodimeric double-barreled architecture of CLC-proteins with two separate Cl-ion transport pathways, one in each subunit. Four of the mammalian CLC proteins, ClC-1, ClC-2, ClC-Ka, and ClC-Kb, are chloride ion channels that fulfill their functional roles-stabilization of the membrane potential, transepithelial salt transport, and ion homeostasisin the plasma membrane. The other five CLC proteins are predominantly expressed in intracellular organelles like endosomes and lysosomes, where they are probably important for a proper luminal acidification, in concert with the V-type H+-ATPase. Surprisingly, ClC-4, ClC-5, and probably also ClC-3, are not Cl- ion channels but exhibit significant Cl-/H+ antiporter activity, as does the bacterial homolog ClC-ec1 and the plant homolog AtCLCa. The physiological significance of the Cl-/H+ antiport activity remains to be established.
Collapse
Affiliation(s)
- G Zifarelli
- CNR, Istituto di Biofisica, Via De Marini 6, 16149 Genova, Italy
| | | |
Collapse
|
33
|
Hansen RS, Diness TG, Christ T, Wettwer E, Ravens U, Olesen SP, Grunnet M. Biophysical Characterization of the New Human Ether-A-Go-Go-Related Gene Channel Opener NS3623 [N-(4-Bromo-2-(1H-tetrazol-5-yl)-phenyl)-N′-(3′-trifluoromethylphenyl)urea]. Mol Pharmacol 2006; 70:1319-29. [PMID: 16825484 DOI: 10.1124/mol.106.026492] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Within the field of new antiarrhythmic compounds, the interesting idea of activating human ether-a-go-go-related gene (HERG1) potassium channels has recently been introduced. Potentially, drugs that increase HERG1 channel activity will augment the repolarizing current of the cardiac myocytes and stabilize the diastolic interval. This may make the myocardium more resistant to events that cause arrhythmias. We here present the compound N-(4-bromo-2-(1H-tetrazol-5-yl)-phenyl)-N'-(3'-trifluoromethylphenyl)urea (NS3623), which has the ability to activate HERG1 channels expressed in Xenopus laevis oocytes with an EC50 value of 79.4 microM. Exposure of HERG1 channels to NS3623 affects the voltage-dependent release from inactivation, resulting in a half-inactivation voltage that is rightward-shifted by 17.7 mV. Moreover, the compound affects the time constant of inactivation, leading to a slower onset of inactivation of the macroscopic HERG1 currents. We also characterized the ability of NS3623 to increase the activity of different mutated HERG1 channels. The mutants S620T and S631A are severely compromised in their ability to inactivate. Application of NS3623 to any of these two mutants did not result in increased HERG1 current. In contrast, application of NS3623 to the mutant F656M increased HERG1 current to a larger extent than what was observed with wild-type HERG1 channels. Because the amino acid F656 is essential for high-affinity inhibition of HERG1 channels, it is concluded that NS3623 has a dual mode of action, being both an activator and an inhibitor of HERG1 channels. Finally, we show that NS3623 has the ability to shorten action potential durations in guinea pig papillary muscle.
Collapse
|
34
|
Steinberg MH. Pathophysiologically based drug treatment of sickle cell disease. Trends Pharmacol Sci 2006; 27:204-10. [PMID: 16530854 DOI: 10.1016/j.tips.2006.02.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Revised: 12/01/2005] [Accepted: 02/21/2006] [Indexed: 01/18/2023]
Abstract
Sickle cell disease is a systemic disorder that is caused by a mutation (Glu6Val) in the gene that encodes beta globin. The sickle hemoglobin molecule (HbS) is a tetramer of two alpha-globin chains and two sickle beta-globin chains, and has the tendency to polymerize when deoxygenated. HbS facilitates abnormal interactions between the sickle erythrocyte and leukocytes and endothelial cells, which trigger a complex pathobiology. This multifaceted pathophysiology provides the opportunity to interrupt the disease at multiple sites, including polymerization of HbS, erythrocyte density and cell-cell interactions. For example, it is possible to induce higher concentrations of fetal hemoglobin, which disrupts the pathology-initiating step of HbS polymerization. Furthermore, it is possible to improve the hydration of sickle erythrocytes and it might be feasible to counteract the endothelial, inflammatory and oxidative abnormalities of sickle cell disease. A therapeutic approach that targets several sites of pathobiology might be most promising.
Collapse
Affiliation(s)
- Martin H Steinberg
- Center of Excellence in Sickle Cell Disease, E248, Boston Medical Center, 88 E. Newton Street, Boston, MA 02118, USA.
| |
Collapse
|
35
|
Abstract
It was recently shown that the putative bacterial Cl- channel, ClC-ec1, is in reality a Cl--H+ antiporter. Our group has now shown that this is also the case for two human CLCs, ClC-4 and ClC-5. We found that the flux of Cl- in one direction is stoichiometrically coupled to the movement of protons in the opposite direction, unveiling a behaviour that is typical of a transporter rather than a channel. This discovery will surely stimulate further research to elucidate the molecular elements responsible for the behaviour as a transporter. On the physiological level, the antiport activity of ClC-4/ClC-5 must lead to a review of the role of CLC proteins in intracellular compartments. Small organic molecules have been extremely useful tools for studying ion channels and many commercial drugs target specific ion channel proteins. Several blockers have been found to inhibit the plasma membrane-localized CLC channels ClC-0, ClC-1 and ClC-Ka. These compounds include 9-anthracene-carboxylic acid (9-AC), p-chlorophenoxy-propionic acid (CPP) and its derivatives, and 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS). Two different binding sites have been identified, one extracellular and one intracellular. However, high-affinity ligands for most CLC proteins are still missing. Apart from being useful biophysical tools, such drugs may provide a way to modulate protein function in vivo. With these tasks to be accomplished, it is definitely an exciting time in the chloride transport field.
Collapse
Affiliation(s)
- M Pusch
- Istituto di biofisica, CNR, Via De Marini 6, I-16149 Genova, Italy.
| | | | | | | | | |
Collapse
|
36
|
Chernova MN, Vandorpe DH, Clark JS, Alper SL. Expression of the polycystin-1 C-terminal cytoplasmic tail increases Cl channel activity in Xenopus oocytes. Kidney Int 2005; 68:632-41. [PMID: 16014040 DOI: 10.1111/j.1523-1755.2005.00441.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Expression of the polycystin-1 C-terminal cytoplasmic tail increases Cl(-) channel activity in Xenopus oocytes. Background. Cyst expansion in autosomal-dominant polycystic kidney disease (ADPKD) is characterized by active Cl(-) secretion in excess of solute reabsorption. However, the connections between elevated epithelial Cl(-) secretion and loss-of-function or dysregulation of either ADPKD gene polycystin-1 (PC1) or polycystin-2 (PC2) remain little understood. Methods. Cl(-) transport in Xenopus oocytes expressing the CD16.7-PKD1 (115-226) fusion protein containing the final 112 amino acid (aa) of the PC1 C-terminal cytoplasmic tail, or in oocytes expressing related PC1 fusion protein mutants, was studied by isotopic flux, two-electrode voltage clamp, and outside-out patch clamp recording. Results. Expression in oocytes of CD16.7-PKD1 (115-226) increased rates of both influx and efflux of (36)Cl(-), whereas CD16.7-PKD1 (1-92) containing the initial 92 aa of the PC1 C-terminal cytoplasmic tail was inactive. The increased Cl(-) transport resembled CD16.7-PKD1 (115-226)-stimulated cation current in its sensitivity to ADPKD-associated missense mutations, to mutations in phosphorylation sites, and to mutations within or encroaching upon the PC1 coiled-coil domain, as well as in its partial suppression by coexpressed PC2. The NS3623- and 4, 4'-diisothiocyanatostilbene-2, 2'-disulfonic acid (DIDS)-sensitive (36)Cl(-) flux was not blocked by injected ethyleneglycol tetraacetate (EGTA) or by the cation channel inhibitor SKF96365, and was stimulated by the cation channel inhibitor La(3+), suggesting that CD16.7-PKD1 (115-226)-associated cation conductance was not required for (36)CI(-) flux activation. Outside-out patches from oocytes expressing CD16.7-PKD1 (115-226) also exhibited increased NS3623-sensitive Cl(-) current. Conclusion. These data show that CD16.7-PKD1 (115-226) activates Cl(-) channels in the Xenopus oocyte plasma membrane in parallel with, but not secondary to, activation of Ca(2+)-permeable cation channels.
Collapse
Affiliation(s)
- Marina N Chernova
- Molecular and Vascular Medicine Unit and Renal Division, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | | | | | | |
Collapse
|
37
|
Petibois C, Déléris G. Erythrocyte Adaptation to Oxidative Stress in Endurance Training. Arch Med Res 2005; 36:524-31. [PMID: 16099333 DOI: 10.1016/j.arcmed.2005.03.047] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2005] [Accepted: 03/30/2005] [Indexed: 11/25/2022]
Abstract
BACKGROUND We tested the hypothesis that endurance training may reduce exercise oxidative stress damage on erythrocytes. METHODS Fifteen subjects performed a standardized endurance exercise at 75% of maximal oxygen consumption weekly during a 19-week training period. Blood samples taken before and after exercise were analyzed by Fourier transform-infrared (FT-IR) spectrometry to determine exercise-induced change in plasma concentrations and erythrocyte IR absorptions. RESULTS Training first induced a stabilization of plasma concentration changes during exercise (unchanged for glucose, increased for lactate, triglycerides, glycerol, and fatty acids), whereas erythrocyte phospholipid alterations remained elevated (p <0.05). Further, training reduced the exercise-induced erythrocyte lactate content increase (nuC-O; p <0.05) and phospholipid alterations (nuC-H(n) and nuP=O; p <0.05) during exercise. These changes paralleled the decrease of exercise-induced hemoconcentration (p <0.05) and plasma lactate increase (p <0.05). CONCLUSIONS These correlated changes between plasma and erythrocyte parameters suggest that endurance training reduces erythrocyte susceptibility to oxidative stress.
Collapse
Affiliation(s)
- Cyril Petibois
- Groupe de Chimie Bio-Organique, Université Victor Segalen Bordeaux 2, France.
| | | |
Collapse
|
38
|
Abdulmalik O, Safo MK, Chen Q, Yang J, Brugnara C, Ohene-Frempong K, Abraham DJ, Asakura T. 5-hydroxymethyl-2-furfural modifies intracellular sickle haemoglobin and inhibits sickling of red blood cells. Br J Haematol 2005; 128:552-61. [PMID: 15686467 DOI: 10.1111/j.1365-2141.2004.05332.x] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
In an attempt to find new types of anti-sickling agents that specifically bind to intracellular sickle haemoglobin (HbS) without inhibition by plasma and tissue proteins or other undesirable consequences, we identified 5-hydroxymethyl-2-furfural (5HMF), a naturally occurring aromatic aldehyde, as an agent that fulfils this criterion. Preliminary studies in vitro showed that 5HMF forms a high-affinity Schiff-base adduct with HbS and inhibits red cell sickling by allosterically shifting oxygen equilibrium curves towards the left. Further studies with transgenic (Tg) sickle mice showed that orally administered 5HMF was rapidly absorbed into the bloodstream from the gastrointestinal tract without being destroyed, traversed the red blood cell membrane and specifically bound with, and modified, HbS molecules at levels as high as 90%. Pretreatment of Tg sickle mice with 5HMF inhibited the formation of sickle cells and significantly prolonged survival time under severe hypoxia, compared with untreated mice, which died within 15 min because of sickling-dependent pulmonary sequestration. These results indicate the feasibility of 5HMF as an attractive potential candidate for therapy of sickle cell disease.
Collapse
Affiliation(s)
- Osheiza Abdulmalik
- Division of Hematology, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Abstract
Polymers of deoxyhemoglobin S deform sickle cell anemia red blood cells into sickle shapes, leading to the formation of dense, dehydrated red blood cells with a markedly shortened life-span. Nearly four decades of intense research in many laboratories has led to a mechanistic understanding of the complex events leading from sickling-induced permeabilization of the red cell membrane to small cations, to the generation of the heterogeneity of age and hydration condition of circulating sickle cells. This review follows chronologically the major experimental findings and the evolution of guiding ideas for research in this field. Predictions derived from mathematical models of red cell and reticulocyte homeostasis led to the formulation of an alternative to prevailing gradualist views: a multitrack dehydration model based on interactive influences between the red cell anion exchanger and two K(+) transporters, the Gardos channel (hSK4, hIK1) and the K-Cl cotransporter (KCC), with differential effects dependent on red cell age and variability of KCC expression among reticulocytes. The experimental tests of the model predictions and the amply supportive results are discussed. The review concludes with a brief survey of the therapeutic strategies aimed at preventing sickle cell dehydration and with an analysis of the main open questions in the field.
Collapse
Affiliation(s)
- Virgilio L Lew
- Physiological Laboratory, University of Cambridge, United Kingdom.
| | | |
Collapse
|
40
|
Chernova MN, Jiang L, Friedman DJ, Darman RB, Lohi H, Kere J, Vandorpe DH, Alper SL. Functional comparison of mouse slc26a6 anion exchanger with human SLC26A6 polypeptide variants: differences in anion selectivity, regulation, and electrogenicity. J Biol Chem 2004; 280:8564-80. [PMID: 15548529 DOI: 10.1074/jbc.m411703200] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The unusually low 78% amino acid identity between the orthologous human SLC26A6 and mouse slc26a6 polypeptides prompted systematic comparison of their anion transport functions in Xenopus oocytes. Multiple human SLC26A6 variant polypeptides were also functionally compared. Transport was studied as unidirectional fluxes of (36)Cl(-), [(14)C]oxalate, and [(35)S]sulfate; as net fluxes of HCO(3)(-) by fluorescence ratio measurement of intracellular pH; as current by two-electrode voltage clamp; and as net Cl(-) flux by fluorescence intensity measurement of relative changes in extracellular and intracellular [Cl(-)]. Four human SLC26A6 polypeptide variants each exhibited rates of bidirectional [(14)C]oxalate flux, Cl(-)/HCO(3)(-) exchange, and Cl(-)/OH(-) exchange nearly equivalent to those of mouse slc26a6. Cl(-)/HCO(3)(-) exchange by both orthologs was cAMP-sensitive, further enhanced by coexpressed wild type cystic fibrosis transmembrane regulator but inhibited by cystic fibrosis transmembrane regulator DeltaF508. However, the very low rates of (36)Cl(-) and [(35)S]sulfate transport by all active human SLC26A6 isoforms contrasted with the high rates of the mouse ortholog. Human and mouse orthologs also differed in patterns of acute regulation. Studies of human-mouse chimeras revealed cosegregation of the high (36)Cl(-) transport phenotype with the transmembrane domain of mouse slc26a6. Mouse slc26a6 and human SLC26A6 each mediated electroneutral Cl(-)/HCO(3)(-) and Cl(-)/OH(-) exchange. In contrast, whereas Cl(-)/oxalate exchange by mouse slc26a6 was electrogenic, that mediated by human SLC26A6 appeared electroneutral. The increased currents observed in oocytes expressing either mouse or human ortholog were pharmacologically distinct from the accompanying monovalent anion exchange activities. The human SLC26A6 polypeptide variants SLC26A6c and SLC26A6d were inactive as transporters of oxalate, sulfate, and chloride. Thus, the orthologous mouse and human SLC26A6 proteins differ in anion selectivity, transport mechanism, and acute regulation, but both mediate electroneutral Cl(-)/HCO(3)(-) exchange.
Collapse
Affiliation(s)
- Marina N Chernova
- Molecular and Vascular Medicine Unit and Renal Unit, Beth Israel Deaconess Medical Center and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215, USA
| | | | | | | | | | | | | | | |
Collapse
|
41
|
Petibois C, Deleris G. Oxidative stress effects on erythrocytes determined by FT-IR spectrometry. Analyst 2004; 129:912-6. [PMID: 15457322 DOI: 10.1039/b408931f] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study was designed to evaluate changes in erythrocyte contents during endurance moderate intensity exercise, a model of physiological oxidative stress. 16 endurance-trained subjects cycled 2 h at 55% of maximal aerobic capacity and blood was collected every 15 min. Transmission FT-IR spectrometry was used to analyze separately plasma and erythrocyte content changes during oxidative stress. Erythrocyte FT-IR spectra were corrected for hemoconcentration (Hc) before spectral areas integration of main IR absorbances belonging to phospholipids [nu(as)(CH(3)), [nu(as)(CH(2)), and nu(P=O)], proteins [nu(C=O) and delta(N-H)], and lactate [nu(C-O)] were used to determine erythrocyte content changes. Changes in nu(as)(CH(2)) and nu(P=O) absorbances while nu(as)(CH(3)) remained stable showed the magnitude of free radical attacks on phospholipids bilayer. Decrease in nu(C=O) and delta(N-H) absorbances while plasma and intracellular lactate, O(2) consumption, and Hc rose were linked to hemoglobin, and possibly spectrin, denaturation. Finally, the synergistic changes found between physiological, plasmatic and erythrocyte parameters showed that FT-IR spectrometry was a sufficiently accurate and sensitive method to determine acute changes in erythrocytes during moderate, physiological, oxidative stress.
Collapse
Affiliation(s)
- Cyril Petibois
- INSERM U577, Groupe de Chimie Bio-Organique, Universite Victor Segalen Bordeaux 2, 33046 Bordeaux, France
| | | |
Collapse
|
42
|
Hélix N, Strøbaek D, Dahl BH, Christophersen P. Inhibition of the endogenous volume-regulated anion channel (VRAC) in HEK293 cells by acidic di-aryl-ureas. J Membr Biol 2004; 196:83-94. [PMID: 14724745 DOI: 10.1007/s00232-003-0627-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2003] [Indexed: 10/26/2022]
Abstract
The endogenous volume-regulated anion channel (VRAC) from HEK293 cells was pharmacologically characterized using the whole-cell patch-clamp technique. Under isotonic conditions a small (1.3 nS), Ca(2+)-independent Cl conductance was measured. However, swelling at 75% tonicity activated a VRAC identified as an outward-rectifying anion current ( P(l) > P(Cl) > P(gluconate)), which was ATP-dependent and showed inactivation at positive potentials. Activation of this current followed a sigmoid time course, reaching a plateau conductance of 42.6 nS after 12-15 min ( t(1/2) = 7 min). The pharmacology of this VRAC was investigated using standard Cl(-)-channel blockers (NPPB, DIDS, and tamoxifen) as well as a new group (acidic di-aryl ureas) of Cl(-)-channel blockers (NS1652, NS3623, NS3749, and NS3728). The acidic di-aryl ureas were originally synthezised for inhibition of the human erythrocyte Cl(-) conductance in vivo. NS3728 was the most potent VRAC blocker in this series ( IC(50) = 0.40 micro M) and even more potent than tamoxifen (2.2 micro M). NS3728 accelerated channel inactivation at positive potentials. These results show that acidic di-aryl ureas constitute a promising starting point for the synthesis of potent inhibitors of VRAC.
Collapse
Affiliation(s)
- N Hélix
- NeuroSearch A/S, Pederstrupvej 93, DK-2750, Ballerup, Denmark
| | | | | | | |
Collapse
|
43
|
Schaller S, Henriksen K, Sveigaard C, Heegaard AM, Hélix N, Stahlhut M, Ovejero MC, Johansen JV, Solberg H, Andersen TL, Hougaard D, Berryman M, Shiødt CB, Sørensen BH, Lichtenberg J, Christophersen P, Foged NT, Delaissé JM, Engsig MT, Karsdal MA. The chloride channel inhibitor NS3736 [corrected] prevents bone resorption in ovariectomized rats without changing bone formation. J Bone Miner Res 2004; 19:1144-53. [PMID: 15176998 DOI: 10.1359/jbmr.040302] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2003] [Revised: 01/26/2004] [Accepted: 02/26/2004] [Indexed: 01/21/2023]
Abstract
UNLABELLED Chloride channel activity is essential for osteoclast function. Consequently, inhibition of the osteoclastic chloride channel should prevent bone resorption. Accordingly, we tested a chloride channel inhibitor on bone turnover and found that it inhibits bone resorption without affecting bone formation. This study indicates that chloride channel inhibitors are highly promising for treatment of osteoporosis. INTRODUCTION The chloride channel inhibitor, NS3736, blocked osteoclastic acidification and resorption in vitro with an IC50 value of 30 microM. When tested in the rat ovariectomy model for osteoporosis, daily treatment with 30 mg/kg orally protected bone strength and BMD by approximately 50% 6 weeks after surgery. Most interestingly, bone formation assessed by osteocalcin, mineral apposition rate, and mineralized surface index was not inhibited. MATERIALS AND METHODS Analysis of chloride channels in human osteoclasts revealed that ClC-7 and CLIC1 were highly expressed. Furthermore, by electrophysiology, we detected a volume-activated anion channel on human osteoclasts. Screening 50 different human tissues showed a broad expression for CLIC1 and a restricted immunoreactivity for ClC-7, appearing mainly in osteoclasts, ovaries, appendix, and Purkinje cells. This highly selective distribution predicts that inhibition of ClC-7 should specifically target osteoclasts in vivo. We suggest that NS3736 is inhibiting ClC-7, leading to a bone-specific effect in vivo. RESULTS AND CONCLUSION In conclusion, we show for the first time that chloride channel inhibitors can be used for prevention of ovariectomy-induced bone loss without impeding bone formation. We speculate that the coupling of bone resorption to bone formation is linked to the acidification of the resorption lacunae, thereby enabling compounds that directly interfere with this process to be able to positive uncouple this process resulting in a net bone gain.
Collapse
|
44
|
Maher AD, Kuchel PW. The Gárdos channel: a review of the Ca2+-activated K+ channel in human erythrocytes. Int J Biochem Cell Biol 2003; 35:1182-97. [PMID: 12757756 DOI: 10.1016/s1357-2725(02)00310-2] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Ca(2+)-dependent K(+) efflux from human erythrocytes was first described in the 1950s. Subsequent studies revealed that a K(+)-specific membrane protein (the Gárdos channel) was responsible for this phenomenon (the Gárdos effect). In recent years several types of Ca-activated K(+) channel have been identified and studied in a wide range of cells, with the erythrocyte Gárdos channel serving as both a model for a broader physiological perspective, and an intriguing component of erythrocyte function. The existence of this channel has raised a number of questions. For example, what is its role in the establishment and maintenance of ionic distribution across the red cell membrane? What role might it play in erythrocyte development? To what extent is it active in circulating erythrocytes? What are the cell-physiological implications of its dysfunction?This review summarises current knowledge of this membrane protein with respect to its function and structure, its physiological roles (some putative) and its contribution to various disease states, and it provides an introduction to adaptable NMR methods, which is our own area of technical expertise, for such ion transport analysis.
Collapse
Affiliation(s)
- Anthony D Maher
- School of Molecular and Microbial Biosciences G08, University of Sydney, NSW 2006, Australia
| | | |
Collapse
|
45
|
Abstract
Sickle hemoglobin (HbS), as a result of its polymer-related and oxidant effects, damages the sickle erythrocyte, provokes inflammation, and causes endothelial injury. All these elements cause the phenotype of sickle cell disease. Novel treatments inhibit HbS polymerization by inducing fetal hemoglobin expression, prevent or repair erythrocyte dehydration by slowing cellular potassium and water loss, and replace HbS-producing erythroid progenitors by stem cell transplantation. Future treatment prospects include gene therapy, interruption of the interaction of sickle cells with the endothelium, inhibition of oxidative damage, and protection of an injured endothelium.
Collapse
Affiliation(s)
- Martin H Steinberg
- Department of Medicine and Pediatrics, Boston University School of Medicine, 88 E Newton Street, Boston, Massachusetts 02118, USA.
| | | |
Collapse
|
46
|
Stummann TC, Poulsen JH, Hay-Schmidt A, Grunnet M, Klaerke DA, Rasmussen HB, Olesen SP, Jorgensen NK. Pharmacological investigation of the role of ion channels in salivary secretion. Pflugers Arch 2003; 446:78-87. [PMID: 12690466 DOI: 10.1007/s00424-002-0985-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2002] [Accepted: 10/29/2002] [Indexed: 01/01/2023]
Abstract
The role of K+ and Cl- channels in salivary secretion was investigated, with emphasis on the potential role of Ca2+ -activated K+ channels. Ligand saturation kinetic assays and autoradiography showed large-conductance (BK) K+ channels to be highly expressed in rat submandibular and parotid glands, whereas low-conductance (SK) K+ channels could not be detected. To investigate the role of K+ and Cl- channels in secretion, intact rabbit submandibular glands were vascularly perfused and secretion induced by 10 microM ACh. Secretion was inhibited by 34+/-3% following perfusion with the general K+ channel inhibitor Ba2+ (5 mM), whereas organic inhibitors of BK (200 nM paxilline) or intermediate-conductance (IK) K+ channels (5 microM clotrimazole) had no effect. Secretion was strongly influenced by Cl- channel inhibitors, as 100 microM 5-nitro-2-(3-phenylpropylamino)benzoate (NPPB) completely abolished, while 10 microM NPPB, 20 microM NS1652 and 20 microM NS3623 reduced secretion by 34+/-3%, 23+/-3% and 59+/-4%, respectively. In conclusion, although high expression levels of BK channels were demonstrated, pharmacological tools failed to demonstrate any role for BK, IK or SK channels in salivary secretion in the rabbit submandibular gland. Other types of K+ channel, however, and particularly Cl- channels, are essential for ACh-induced salivary secretion.
Collapse
Affiliation(s)
- Tina C Stummann
- Department of Medical Physiology, The Panum Institute, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Abstract
A critical link between the single molecular defect in sickle cell anemia and the extensive pathology of this disease is the reversible increase in red cell membrane permeability generated by hemoglobin S polymers in the deoxygenated state. This permeability, usually described as P (sickle), triggers a chain of events in which two constitutive transporters of the red cell membrane become activated-the recently cloned intermediate conductance, Ca 2+ -sensitive K channel, and the electroneutral K:Cl cotransporter-leading to sickle cell dehydration. This article reviews knowledge of the dehydration mechanism, stressing the marked heterogeneity of dehydration rates in sickle cell populations, and discusses recent contributions to understanding of the function and regulation of P (sickle), Ca 2+ -sensitive K channel, and K:Cl cotransporter, and of therapies targeted at these transporters.
Collapse
Affiliation(s)
- Robert M Bookchin
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
| | | |
Collapse
|
48
|
Riddington C, De Franceschi L. Drugs for preventing red blood cell dehydration in people with sickle cell disease. Cochrane Database Syst Rev 2002:CD003426. [PMID: 12519597 DOI: 10.1002/14651858.cd003426] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Sickle cell disease is an inherited disorder of haemoglobin, which results in abnormal red blood cells. These can deform and cause blockages in blood vessels, leading to acute crises such as pain, stroke and splenic sequestration, and chronic organ and tissue damage. Recently research has begun to focus on therapies which prevent the red blood cells deforming by reducing the loss of water and ions from the cells. However, little is known about the effectiveness and safety of such drugs. OBJECTIVES To assess the relative risks and benefits of drugs which aim to prevent sickle cell related crises by reducing red blood cell dehydration. SEARCH STRATEGY We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group specialist register which comprises references identified from comprehensive electronic database searches, handsearching relevant journals and handsearching abstract books of conference proceedings. Date of the most recent search of the Group's specialised register: December 2001. SELECTION CRITERIA All those randomised or quasi-randomised controlled trials of drugs which aim to prevent sickle cell crises by reducing red cell dehydration, compared to placebo or an alternative treatment. DATA COLLECTION AND ANALYSIS Both reviewers independently selected trials for inclusion, assessed trial quality and extracted data from the included studies. MAIN RESULTS Of the 27 trials identified, two met the inclusion criteria. The two trials tested the effectiveness of zinc sulphate and piracetam to prevent sickle cell related crises in a total of 246 patients. A reduction in pain crises was shown in the piracetam study over one year (weighted mean difference (WMD) -1.9 (95% CI -3.01, -0.79)), although blood counts were not significantly changed. The zinc trial showed a significant reduction in the total number of pain, haemolytic, aplastic and sequestration crises over one and a half years (WMD -2.83 (95% CI -3.51, -2.15)), but our analysis was limited by non-reporting of standard deviations for some data. Changes to red cell parameters and blood counts were inconsistent. No serious adverse events were noted in either trial. REVIEWER'S CONCLUSIONS While the results of both zinc and piracetam for reducing sickle related crises are encouraging, larger, and/or longer term multicentre trials over a number of years are needed to evaluate the effectiveness of these therapies for patients with sickle cell disease.
Collapse
Affiliation(s)
- C Riddington
- Institute of Child Health, University of Liverpool, Alder Hey Children's Hospital, Eaton Road, Liverpool, UK, L12 2AP.
| | | |
Collapse
|
49
|
Vassiliou G, Amrolia P, Roberts IA. Allogeneic transplantation for haemoglobinopathies. Best Pract Res Clin Haematol 2001; 14:807-22. [PMID: 11924923 DOI: 10.1053/beha.2001.0174] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Beta-thalassaemia major and sickle-cell disease (SCD) reduce lifespan and quality of life for >300000 children and young adults worldwide. The only cure for both disorders is allogeneic stem cell transplantation (SCT). The decision-making processes in recommending SCT for patients with thalassaemia and SCD are different. For thalassaemia, where transfusion-related iron overload is universal, SCT should be offered to all patients <17 years because long-term survival and thalassaemia-free survival are about 80 and 70% respectively. For thalassaemics unable to comply with medical treatment, SCT offers a significant survival advantage; however, for patients with optimal medical care, short-term survival after SCT is inferior to medical treatment, and SCT instead offers a life free from transfusions and iron chelation. The clinical heterogeneity of SCD means that SCT is recommended only for selected patients with severe disease, particularly sickle-related neurological problems, for whom long-term survival and SCD-free survival after SCT approach 92 and 86% respectively. We here review the evidence available to help physicians evaluate the role of SCT for individual patients with thalassaemia major or SCD.
Collapse
Affiliation(s)
- G Vassiliou
- Department of Haematology, Imperial College Faculty of Medicine, Hammersmith Hospital, London, UK
| | | | | |
Collapse
|
50
|
Abstract
The sickle hemoglobin (HbS)-containing erythrocyte and its membrane represent a logical target for sickle cell disease therapy. Several antisickling agents which interfere with HbS polymerization have been studied over the last 30 years, but none has overcome the challenge of delivering high concentrations inside the sickle red blood cell without toxicity. The sickle erythrocyte membrane has also been targeted for therapeutic developments. Prevention of sickle cell dehydration by use of specific blockers of ion transport pathways mediating potassium loss from the sickle erythrocyte has been shown to be a feasible strategy in vitro, in vivo in transgenic sickle mice, and in patients. Other approaches have focused on improving the hemorheology of sickle erythrocytes and reducing their abnormal adhesion to endothelial cells. These potential treatments could be used alone or in combination with other approved therapies, such as hydroxyurea.
Collapse
Affiliation(s)
- C Brugnara
- Department of Laboratory Medicine, Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | | |
Collapse
|