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Aurigemma I, Ferrentino R, Krishnan VP, Lanzetta O, Angelini C, Illingworth E, Baldini A. Significant improvement of cardiac outflow tract septation defects in a DiGeorge syndrome model after minoxidil treatment. Biochem Biophys Res Commun 2024; 720:150104. [PMID: 38749189 PMCID: PMC11166380 DOI: 10.1016/j.bbrc.2024.150104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 05/11/2024] [Indexed: 06/05/2024]
Abstract
The T-BOX transcription factor TBX1 is essential for the development of the pharyngeal apparatus and it is haploinsufficient in DiGeorge syndrome (DGS), a developmental anomaly associated with congenital heart disease and other abnormalities. The murine model recapitulates the heart phenotype and showed collagen accumulation. We first used a cellular model to study gene expression during cardiogenic differentiation of WT and Tbx1-/- mouse embryonic stem cells. Then we used a mouse model of DGS to test whether interfering with collagen accumulation using an inhibitor of lysyl hydroxylase would modify the cardiac phenotype of the mutant. We found that loss of Tbx1 in a precardiac differentiation model was associated with up regulation of a subset of ECM-related genes, including several collagen genes. In the in vivo model, early prenatal treatment with Minoxidil, a lysyl hydroxylase inhibitor, ameliorated the cardiac outflow tract septation phenotype in Tbx1 mutant fetuses, but it had no effect on septation in WT fetuses. We conclude that TBX1 suppresses a defined subset of ECM-related genes. This function is critical for OFT septation because the inhibition of collagen cross-linking in the mutant reduces significantly the penetrance of septation defects.
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Affiliation(s)
| | | | | | - Olga Lanzetta
- Institute of Genetics and Biophysics, CNR, Naples, Italy
| | | | | | - Antonio Baldini
- Dept of Molecular Medicine and Medical Biotechnology, Univ. Federico II, Naples, Italy.
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Kieling L, Konzen AT, Zanella RK, Valente DS. Is autologous platelet-rich plasma capable of increasing hair density in patients with androgenic alopecia? A systematic review and meta-analysis of randomized clinical trials ⋆. An Bras Dermatol 2024:S0365-0596(24)00136-3. [PMID: 39013743 DOI: 10.1016/j.abd.2024.01.002] [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: 08/02/2023] [Revised: 12/18/2023] [Accepted: 01/12/2024] [Indexed: 07/18/2024] Open
Abstract
FUNDAMENTALS Platelet-rich plasma (PRP) has been progressively more used in androgenetic alopecia (AGA). OBJECTIVES The authors aimed to evaluate PRP efficacy compared to placebo in AGA. METHODS A comprehensive search was conducted across seven databases, until 01/04/2023. Randomized clinical trials focusing on AGA and PRP use to increase hair density were included. Patients aged between 15 and 63 years, diagnosed with AGA characterized by Norwood I‒VII and Ludwig I‒III scales, were included. Studies with a sample size <10, lacking PRP processing method, focusing on complementary therapies or other alopecias, were excluded. The authors conducted subgroup analysis for activator, spin method, study design, risk of bias, and gender. Meta-regression was conducted for activator, spin method, design, and gender. The authors used GRADEpro to assess evidence certainty and the RoB-2 tool for risk of bias. Asymmetry was measured through a Funnel plot followed by Egger's test. The protocol was registered at PROSPERO (CRD42023407334). RESULTS The authors screened 555 registers and included fourteen studies involving 431 patients for qualitative synthesis, with 13 studies included in the meta-analysis. Meta-analysis demonstrated a mean difference of 27.55 hairs/cm2 and 95% CI (14.04; 41.06), I2 = 95.99%, p < 0.05. Hair diameter meta-analysis presented a mean difference of 2.02 μm, 95% CI (-0.85 μm; 4.88 μm), and I2 = 77.11% (p = 0.02). That is, low quality evidence. LIMITATIONS OF THE STUDY Studies were highly heterogeneous, of low quality, and presented evident publication bias. CONCLUSIONS Highly heterogeneous studies with publication bias suggest PRP effectively increases hair density in AGA, so further high-quality randomized clinical trials are recommended to strengthen the evidence.
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Affiliation(s)
- Lucas Kieling
- Division of Surgical Clinics, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil.
| | - Ana Terezinha Konzen
- Division of Surgical Clinics, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil
| | - Rafaela Koehler Zanella
- Graduate Program in Medicine and Health Sciences, Faculdade de Medicina da Pontifícia, Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Denis Souto Valente
- Division of Surgical Clinics, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil
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Akinleye A, Jamil Y, Dogbey P. Minoxidil-Induced Pleuro-Pericardial Effusion With Tamponade. Cureus 2023; 15:e46416. [PMID: 37927730 PMCID: PMC10621627 DOI: 10.7759/cureus.46416] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2023] [Indexed: 11/07/2023] Open
Abstract
Minoxidil-induced pleuro-pericardial effusion is a diagnosis of exclusion after evaluation for other known causes of pericardial effusion. When complicated by cardiac tamponade, prompt pericardiocentesis and discontinuation of minoxidil can be lifesaving. We report a rare case of minoxidil-induced pleuro-pericardial effusion with tamponade in a patient with end-stage renal disease (ESRD) on hemodialysis who improved with pericardiocentesis and drug withdrawal.
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Affiliation(s)
- Akintayo Akinleye
- Internal Medicine, Yale School of Medicine, Yale-Waterbury Internal Medicine Program, Waterbury, USA
| | - Yasser Jamil
- Internal Medicine, Yale School of Medicine, Yale-Waterbury Internal Medicine Program, Waterbury, USA
| | - Pia Dogbey
- Internal Medicine, Yale School of Medicine, Yale-Waterbury Internal Medicine Program, Waterbury, USA
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Wang T, Liu T, Xu S, Frindt G, Weinstein AM, Palmer LG. High dietary K + intake inhibits proximal tubule transport. Am J Physiol Renal Physiol 2023; 325:F224-F234. [PMID: 37318989 PMCID: PMC10396284 DOI: 10.1152/ajprenal.00013.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/15/2023] [Accepted: 06/14/2023] [Indexed: 06/17/2023] Open
Abstract
The impact of chronic dietary K+ loading on proximal tubule (PT) function was measured using free-flow micropuncture along with measurements of overall kidney function, including urine volume, glomerular filtration rate, and absolute and fractional Na+ and K+ excretion in the rat. Feeding animals a diet with 5% KCl [high K+ (HK)] for 7 days reduced glomerular filtration rate by 29%, increased urine volume by 77%, and increased absolute K+ excretion by 202% compared with rats on a 1% KCl [control K+ (CK)] diet. HK did not change absolute Na+ excretion but significantly increased fraction excretion of Na+ (1.40% vs. 0.64%), indicating that fractional Na+ absorption is reduced by HK. PT reabsorption was assessed using free-flow micropuncture in anesthetized animals. At 80% of the accessible length of the PT, measurements of inulin concentration indicated volume reabsorption of 73% and 54% in CK and HK, respectively. At the same site, fractional PT Na+ reabsorption was 66% in CK animals and 37% in HK animals. Fractional PT K+ reabsorption was 66% in CK and 37% in HK. To assess the role of Na+/H+ exchanger isoform 3 (NHE3) in mediating these changes, we measured NHE3 protein expression in total kidney microsomes as well as surface membranes using Western blots. We found no significant changes in protein in either cell fraction. Expression of the Ser552 phosphorylated form of NHE3 was also similar in CK and HK animals. Reduction in PT transport may facilitate K+ excretion and help balance Na+ excretion by shifting Na+ reabsorption from K+-reabsorbing to K+-secreting nephron segments.NEW & NOTEWORTHY In rats fed a diet rich in K+, proximal tubules reabsorbed less fluid, Na+, and K+ compared with those in animals on a control diet. Glomerular filtration rates also decreased, probably due to glomerulotubular feedback. These reductions may help to maintain balance of the two ions simultaneously by shifting Na+ reabsorption to K+-secreting nephron segments.
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Affiliation(s)
- Tong Wang
- Department of Molecular and Cellular Physiology, Yale University School of Medicine, New Haven, Connecticut, United States
| | - Tommy Liu
- Department of Molecular and Cellular Physiology, Yale University School of Medicine, New Haven, Connecticut, United States
| | - Shuhua Xu
- Department of Molecular and Cellular Physiology, Yale University School of Medicine, New Haven, Connecticut, United States
| | - Gustavo Frindt
- Department of Physiology and Biophysics, Weill-Cornell Medicine, New York, New York, United States
| | - Alan M Weinstein
- Department of Physiology and Biophysics, Weill-Cornell Medicine, New York, New York, United States
| | - Lawrence G Palmer
- Department of Physiology and Biophysics, Weill-Cornell Medicine, New York, New York, United States
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Gbadamosi WA, Melvin J, Lopez M. Atypical Case of Minoxidil-Induced Generalized Anasarca and Pleuropericardial Effusion. Cureus 2021; 13:e15424. [PMID: 34249570 PMCID: PMC8253457 DOI: 10.7759/cureus.15424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2021] [Indexed: 11/29/2022] Open
Abstract
Minoxidil is an antihypertensive medication used to control blood pressure that is resistant to three or more antihypertensive medications including diuretics. There have only been a few reported cases of minoxidil-induced pleuropericardial effusion with anasarca. Here, we discuss the case of a 70-year-old male with a history of uncontrolled hypertension who presented to the hospital with swelling of the extremities. He was on minoxidil 10 mg twice a day and complained of generalized body swelling and extremity pain with symptoms of dyspnea on exertion, paroxysmal nocturnal dyspnea, weight gain, abdominal distention, and intermittent, throbbing extremity pain (8/10). The patient denied a history of cardiac disease, pulmonary embolism, deep vein thrombosis, and malignancy. His vitals were stable with a blood pressure of 152/67 mmHg. The physical examination findings were significant for positive jugular vein pressure, bilateral crackles at the lung bases with abdominal distention, fluid thrill, and flank edema. The extremities showed pitting edema in the upper and lower extremities that were tender to palpation. Laboratory results were only significant for uremia and elevated brain natriuretic peptide. Electrocardiography, echocardiography, and CT of the chest and abdomen exhibited findings consistent with pericardial effusion, pleural effusion, abdominal ascites, and anasarca in the soft tissues of the axilla and chest wall. After discontinuation of minoxidil and starting intravenous diuretics, the patient showed clinical improvement. This case report reviews and explains that minoxidil-induced anasarca should be considered as a differential diagnosis in patients taking minoxidil as knowledge of this rare finding may lead to early diagnosis and management.
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Affiliation(s)
| | | | - Marvin Lopez
- Internal Medicine, Coliseum Medical Centers, Macon, USA
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6
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Boland PA, Kelly ME, Donlon NE, Bolger JC, Larkin JO, Mehigan BJ, McCormick PH. Management options for chronic anal fissure: a systematic review of randomised controlled trials. Int J Colorectal Dis 2020; 35:1807-1815. [PMID: 32712929 DOI: 10.1007/s00384-020-03699-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/14/2020] [Indexed: 02/04/2023]
Abstract
INTRODUCTION Anal fissure is the most common cause of severe anorectal pain in adults, contributing significantly to coloproctology workloads. There are a wide variety of management options available, including topical nitrites, calcium channel blockers, botulinum toxin injection and sphincterotomy. The aim of this study was to review current options for the treatment of chronic anal fissure. METHODS A comprehensive search identifying randomized controlled trials comparing treatment options for anal fissure published between January 2000 and February 2020 was performed. The primary outcome assessed was healing at 8 weeks post commencing treatment. Secondary outcomes included recurrence, intolerance of treatment and complications. RESULTS A total of 2822 studies were identified. After removal of duplicates and non-relevant studies, we identified nine randomized controlled trials which met pre-defined criteria. There was a total of 775 patients. At 8 weeks, healing rates were 95.13% in those treated with sphincterotomy, 66.7% in the botulinum toxin group, 63.8% in the nitrate group, 52.3% for topical diltiazem and 50% for topical minoxidil. Recurrence was highest amongst those treated with botulinum toxin injection (41.7%) and lowest for sphincterotomy (6.9%). Although the absolute number is low, there was a risk of permanent incontinence with sphincterotomy. CONCLUSION This review of the randomized control data demonstrates that healing was significantly higher amongst those treated with sphincterotomy versus more conservative modalities. Topical nitrites had similar outcomes to botulinum toxin injection but were poorly tolerated in comparison to other treatments. The benefit of sphincterotomy was at a cost of increased complications, notably permanent incontinence.
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Affiliation(s)
- P A Boland
- Department of Colorectal Surgery, St James' Hospital, Dublin, 8, Ireland.
| | - M E Kelly
- Department of Colorectal Surgery, St James' Hospital, Dublin, 8, Ireland
| | - N E Donlon
- Department of Colorectal Surgery, St James' Hospital, Dublin, 8, Ireland
| | - J C Bolger
- Department of Colorectal Surgery, St James' Hospital, Dublin, 8, Ireland
| | - J O Larkin
- Department of Colorectal Surgery, St James' Hospital, Dublin, 8, Ireland
| | - B J Mehigan
- Department of Colorectal Surgery, St James' Hospital, Dublin, 8, Ireland
| | - P H McCormick
- Department of Colorectal Surgery, St James' Hospital, Dublin, 8, Ireland
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Wang CC, Wang LK, Chen ML, Kuo CY, Tsai FM, Wang CH. Triterpenes in the Ethanol Extract of Poria cocos Induce Dermal Papilla Cell Proliferation. INT J PHARMACOL 2019. [DOI: 10.3923/ijp.2020.1.9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Gonzalez-Vicente A, Saez F, Monzon CM, Asirwatham J, Garvin JL. Thick Ascending Limb Sodium Transport in the Pathogenesis of Hypertension. Physiol Rev 2019; 99:235-309. [PMID: 30354966 DOI: 10.1152/physrev.00055.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The thick ascending limb plays a key role in maintaining water and electrolyte balance. The importance of this segment in regulating blood pressure is evidenced by the effect of loop diuretics or local genetic defects on this parameter. Hormones and factors produced by thick ascending limbs have both autocrine and paracrine effects, which can extend prohypertensive signaling to other structures of the nephron. In this review, we discuss the role of the thick ascending limb in the development of hypertension, not as a sole participant, but one that works within the rich biological context of the renal medulla. We first provide an overview of the basic physiology of the segment and the anatomical considerations necessary to understand its relationship with other renal structures. We explore the physiopathological changes in thick ascending limbs occurring in both genetic and induced animal models of hypertension. We then discuss the racial differences and genetic defects that affect blood pressure in humans through changes in thick ascending limb transport rates. Throughout the text, we scrutinize methodologies and discuss the limitations of research techniques that, when overlooked, can lead investigators to make erroneous conclusions. Thus, in addition to advancing an understanding of the basic mechanisms of physiology, the ultimate goal of this work is to understand our research tools, to make better use of them, and to contextualize research data. Future advances in renal hypertension research will require not only collection of new experimental data, but also integration of our current knowledge.
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Affiliation(s)
| | - Fara Saez
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Casandra M Monzon
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jessica Asirwatham
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jeffrey L Garvin
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
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Renal outer medullary potassium channel knockout models reveal thick ascending limb function and dysfunction. Clin Exp Nephrol 2011; 16:49-54. [PMID: 22038261 DOI: 10.1007/s10157-011-0495-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Accepted: 03/23/2011] [Indexed: 10/15/2022]
Abstract
The renal outer medullary potassium channel (ROMK) is an adenosine triphosphate-sensitive inward-rectifier potassium channel (Kir1.1 or KCNJ1) highly expressed in the cortical and medullary thick ascending limbs (TAL), connecting segment (CNT) and cortical collecting duct (CCD) in the mammalian kidney, where it serves to recycle potassium (K(+)) across the apical membrane in TAL and to secrete K(+) in the CNT and CCD. ROMK channel mutations cause type II Bartter's syndrome with salt wasting and dehydration, and ROMK knockout mice display a similar phenotype of Bartter's syndrome in humans. Studies from ROMK null mice indicate that ROMK is required to form both the small-conductance (30pS, SK) K channels and the 70pS (IK) K channels in the TAL. The availability of ROMK(-/-) mice has made it possible to study electrolyte transport along the nephron in order to understand the TAL function under physiological conditions and the compensatory mechanisms of salt and water transport under the conditions of TAL dysfunction. This review summarizes previous progress in the study of K(+) channel activity in the TAL and CCD, ion transporter expression and activities along the nephron, and renal functions under physiological and pathophysiological conditions using ROMK(-/-) mice.
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10
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Slim HB, Black HR, Thompson PD. Older blood pressure medications-do they still have a place? Am J Cardiol 2011; 108:308-16. [PMID: 21550576 DOI: 10.1016/j.amjcard.2011.03.041] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 03/11/2011] [Accepted: 03/11/2011] [Indexed: 01/13/2023]
Abstract
Hypertension is a major risk factor for cardiovascular disease, but control of hypertension remains inadequate, often because of poor patient adherence to prescribed medical regimens that are viewed as poorly tolerated and expensive. Physicians have largely stopped using some older blood pressure medications in favor of newer agents, mostly because of a presumed more favorable side effect profile. The investigators reviewed the pharmacologic properties and the evidence supporting the effectiveness and tolerability of several older blood pressure drugs: sympatholytic agents such as reserpine, methyldopa, and clonidine; diuretics such as chlorthalidone, ethacrynic acid and spironolactone; the vasodilators hydralazine and minoxidil; and others. In conclusion, some of these drugs are well studied and represent alternatives for patients who cannot afford or tolerate newer medications.
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Affiliation(s)
- Hanna B Slim
- Cardiology, Hartford Hospital, Connecticut, USA.
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Insulin-induced electrophysiology changes in human pleura are mediated via its receptor. EXPERIMENTAL DIABETES RESEARCH 2010; 2010:853176. [PMID: 20814548 PMCID: PMC2931388 DOI: 10.1155/2010/853176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2010] [Revised: 06/16/2010] [Accepted: 07/02/2010] [Indexed: 11/23/2022]
Abstract
Background. Insulin directly changes the sheep pleural electrophysiology. The aim of this study was to investigate whether insulin induces similar effects in human pleura, to clarify insulin receptor's involvement, and to demonstrate if glibenclamide (hypoglycemic agent) reverses this effect.
Methods. Human parietal pleural specimens were mounted in Ussing chambers. Solutions containing insulin or glibenclamide and insulin with anti-insulin antibody, anti-insulin receptor antibody, and glibenclamide were used. The transmesothelial resistance (RTM) was determined. Immunohistochemistry for the presence of Insulin Receptors (IRa, IRb) was also performed. Results. Insulin increased RTM within 1st min (P = .016), when added mesothelially which was inhibited by the anti-insulin and anti-insulin receptor antibodies. Glibenclamide also eliminated the insulin-induced changes. Immunohistochemistry verified the presence of IRa and IRb.
Conclusion. Insulin induces electrochemical changes in humans as in sheep via interaction with its receptor. This effect is abolished by glibenclamide.
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Black RNA, Hunter SJ, Atkinson AB. Usefulness of the vasodilator minoxidil in resistant hypertension. J Hypertens 2007; 25:1102-3; author reply 1103. [PMID: 17414678 DOI: 10.1097/hjh.0b013e32809c2cc9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Peth S, Karle C, Dehnert C, Bärtsch P, Mairbäurl H. K+ channel activation with minoxidil stimulates nasal-epithelial ion transport and blunts exaggerated hypoxic pulmonary hypertension. High Alt Med Biol 2006; 7:54-63. [PMID: 16544967 DOI: 10.1089/ham.2006.7.54] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Increased pulmonary capillary pressure and inhibition of alveolar Na+ transport putatively contribute to the formation of pulmonary edema in alveolar hypoxia such as at high altitude. Since both events might be linked to the inhibition of K+ channels, we studied whether in vivo application of minoxidil, a stimulator of ATP-gated K channels (K+ ATP channel activator) prevents both effects. In a double- blind, placebo-controlled crossover study on 17 volunteers with no known susceptibility to high altitude pulmonary edema, we tested whether a single dose of minoxidil (5 mg) prevents pulmonary hypertension and inhibition of nasal-epithelial Na+ transport in normobaric hypoxia (12% O2, 2 h). In hypoxia, arterial SO2 was decreased to about 80%, and systolic pulmonary artery pressure (PAP) measured by Doppler echocardiography increased significantly from approximately 25 mmHg (normoxia) to approximately 38 mmHg (hypoxia; range 22 to 61 mmHg). Minoxidil decreased PAP in hypoxia in those individuals who had the highest increase in PAP in hypoxia when taking placebo. Nasal potentials decreased by about 10% in hypoxia. Although minoxidil had no effect on nasal potentials in normoxia, it increased nasal potentials significantly above normoxic control values after 2-h hypoxia. These results show that the K+ ATP activator minoxidil prevents the decrease in nasal-epithelial potential by hypoxia and seems to blunt an exaggerated increase in PAP in acute hypoxia.
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Affiliation(s)
- Simon Peth
- Medical Clinic VII, Sports Medicine, University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany
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14
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Diskin CJ, Stokes TJ, Dansby LM, Radcliff L, Carter TB. Does the Hyperfiltration of Minoxidil Result in Increased Proteinuria and Loss of Renoprotection Conferred by Angiotensin Inhibition? Kidney Blood Press Res 2006; 29:54-9. [PMID: 16645303 DOI: 10.1159/000092947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Accepted: 12/05/2005] [Indexed: 01/13/2023] Open
Abstract
The objective of the present study was to retrospectively examine whether the addition of minoxidil to patients who were already treated with maximum doses of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers but who had not achieved target blood pressures, has any detrimental effect on proteinuria or renal function or whether its effect on blood pressure prove salutary. The clinical records of the patients seen at the Hypertension, Nephrology, Dialysis and Transplantation Clinic from June 1982 through May 2005 were reviewed to identify 54 patients (78% men, 82% African-American) who had taken minoxidil (with and without angiotensin inhibition and blockade) and who had documented 24-hour urines for creatinine clearance and quantification of proteinuria before the initiation of minoxidil and after the blood pressure had stabilized on its final dose. The study was done at the Hypertension, Nephrology, Dialysis and Transplantation Clinic, the regional referral center for renal problems in eastern Alabama, USA. Minoxidil, whether alone or in combination with maximum doses of ACEIs and ARBs, was very successful in reduction of mean arterial pressure, but there was a tendency towards an increase in proteinuria. When minoxidil was given alone, patients demonstrated a trend towards reduction of proteinuria associated with blood pressure reduction; however, when minoxidil was added after the maximal doses of ACEIs and ARBs had been reached there was a significant increase in proteinuria (p = 0.017) on paired comparison in the same patients whose proteinuria had already demonstrated a significant decrease (p = 0.02) on the ACEI and ARB alone despite further significant reduction of blood pressure with the minoxidil (p = 0.003). Renal function deterioration to end stage renal disease correlated with increase in proteinuria (p = 0.03). We conclude that minoxidil was very effective in lowering systemic blood pressure but when given to patients already on maximum doses of ACEI and ARBs, there was an increase in proteinuria which could be interpreted as a detrimental effect having in mind that the blood pressure was significantly lowered.
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Evans JM, Allan AK, Davies SA, Dow JAT. Sulphonylurea sensitivity and enriched expression implicate inward rectifier K+ channels in Drosophila melanogaster renal function. ACTA ACUST UNITED AC 2006; 208:3771-83. [PMID: 16169954 DOI: 10.1242/jeb.01829] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Insect Malpighian (renal) tubules are capable of transporting fluid at remarkable rates. Secondary active transport of potassium at the apical surface of the principal cell must be matched by a high-capacity basolateral potassium entry route. A recent microarray analysis of Drosophila tubule identified three extremely abundant and enriched K(+) channel genes encoding the three inward rectifier channels of Drosophila: ir, irk2 and irk3. Enriched expression of inward rectifier channels in tubule was verified by quantitative RT-PCR, and all three IRKs localised to principal cells of the main segment (and ir and irk3 to the lower tubule) by in situ hybridisation, suggesting roles both in primary secretion and reabsorption. A new splice form of irk2 was also identified. The role of inward rectifiers in fluid secretion was assessed with a panel of selective inhibitors of inward rectifier channels, the antidiabetic sulphonylureas. All completely inhibited fluid secretion, with IC(50)s of 0.78 mmol l(-1) for glibenclamide and approximately 5 mmol l(-1) for tolbutamide, 0.01 mmol l(-1) for minoxidil and 0.1 mmol l(-1) for diazoxide. This pharmacology is consistent with a lower-affinity class of inward rectifier channel that does not form an obligate multimer with the sulphonylurea receptor (SUR), although effects on non-IRK targets cannot be excluded. Glibenclamide inhibited fluid secretion similarly to basolateral K(+)-free saline. Radiolabelled glibenclamide is both potently transported and metabolised by tubule. Furthermore, glibenclamide is capable of blocking transport of the organic dye amaranth (azorubin S), at concentrations of glibenclamide much lower than required to impact on fluid secretion. Glibenclamide thus interacts with tubule in three separate ways; as a potent inhibitor of fluid secretion, as an inhibitor (possibly competitive) of an organic solute transporter and as a substrate for excretion and metabolism.
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Affiliation(s)
- Jennifer M Evans
- Division of Molecular Genetics, Faculty of Biomedical and Life Sciences, University of Glasgow, UK
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Abstract
Minoxidil is a direct vasodilator introduced in the early 1970s for the treatment of hypertension. It is capable of reducing blood pressure in most persons with resistant hypertension where therapy has failed with multidrug regimens. Minoxidil's effect can be limited because of an increase in pulse rate and/or sodium (and water) retention. The latter may prove quite debilitating in some patients. Thus, minoxidil is generally administered with both a diuretic and an agent that can keep pulse rate in check, such as a beta blocker or a combined alpha-beta blocker. The prominent tachycardia with minoxidil can aggravate myocardial ischemia and, if long-standing, leads to left ventricular hypertrophy. Minoxidil has a particularly annoying side effect of hypertrichosis that may limit its use, particularly among women. Minoxidil use is infrequently associated with the idiosyncratic onset of a pericardial effusion. If a patient's hypertension is severe enough to warrant minoxidil therapy, a hypertension specialist should probably become involved in the patient's care. The use of this medication should be limited in view of the availability of effective agents with fewer side effects. There is, however, a place for minoxidil in the treatment of resistant hypertension especially in patients with advanced renal disease.
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Affiliation(s)
- Domenic A Sica
- Department of Medicine, Section of Clinical Pharmacology and Hypertension, Division of Nephrology, Medical College of Virginia of Virginia Commonwealth University, Richmond, VA 23298, USA.
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Scott BN, Yu MJ, Lee LW, Beyenbach KW. Mechanisms of K+ transport across basolateral membranes of principal cells in Malpighian tubules of the yellow fever mosquito, Aedes aegypti. J Exp Biol 2004; 207:1655-63. [PMID: 15073198 DOI: 10.1242/jeb.00932] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
SUMMARY
The mechanisms of K+ entry from the hemolymph into principal cells of Malpighian tubules were investigated in the yellow fever mosquito, Aedes aegypti. The K+ channel blocker Ba2+ (5 mmol l–1) significantly decreased transepithelial (TEP) fluid secretion (Vs) from 0.84 nl min–1 to 0.37 nl min–1 and decreased the K+ concentration in secreted fluid from 119.0 mmol l–1 to 54.3 mmol l–1 with no change in the Cl– concentration. Even though the Na+ concentration increased significantly from 116.8 mmol l–1 to 144.6 mmol l–1, rates of TEP ion secretion significantly decreased for all three ions. In addition,Ba2+ had the following significant electrophysiological effects: it depolarized the TEP voltage (Vt) from 19.4 mV to 17.2 mV,increased the TEP resistance (Rt) from 6.4 kΩcm to 6.9 kΩcm, hyperpolarized the basolateral membrane voltage of principal cells (Vbl) from –75.2 mV to –88.2 mV and increased the cell input resistance from 363.7 kΩ to 516.3 kΩ. These effects of Ba2+ reflect the block of K+ channels that, apparently, are also permeable to Na+. Bumetanide (100μmol l–1) had no effect on TEP fluid secretion and electrical resistance but significantly decreased TEP K+ secretion,consistent with the inhibition of electroneutral Na+/K+/2Cl– cotransport. TEP Na+ secretion significantly increased because other Na+entry pathways remained active. Bumetanide plus Ba2+ completely inhibited TEP electrolyte and fluid secretion, with fast and slow kinetics reflecting the Ba2+ block of basolateral membrane K+channels and the inhibition of Na+/K+/2Cl– cotransport, respectively. The single and combined effects of Ba2+ and bumetanide suggest that(1) K+ channels and Na+/K+/2Cl– cotransport are the primary mechanisms for bringing K+ into cells, (2) K+ channels mediate a significant Na+ influx, (3) Na+ has as many as four entry pathways and (4) the mechanisms of TEP K+ and Na+ secretion are coupled such that complete block of TEP K+ renders the epithelium unable to secrete Na+.
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Affiliation(s)
- Brett N Scott
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA
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Gosmanov AR, Fan Z, Mi X, Schneider EG, Thomason DB. ATP-sensitive potassium channels mediate hyperosmotic stimulation of NKCC in slow-twitch muscle. Am J Physiol Cell Physiol 2003; 286:C586-95. [PMID: 14592811 DOI: 10.1152/ajpcell.00247.2003] [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] [Indexed: 11/22/2022]
Abstract
In mildly hyperosmotic medium, activation of the Na+ -K+ -2Cl- cotransporter (NKCC) counteracts skeletal muscle cell water loss, and compounds that stimulate protein kinase A (PKA) activity inhibit the activation of the NKCC. The aim of this study was to determine the mechanism for PKA inhibition of NKCC activity in resting skeletal muscle. Incubation of rat slow-twitch soleus and fast-twitch plantaris muscles in isosmotic medium with the PKA inhibitors H-89 and KT-5720 caused activation of the NKCC only in the soleus muscle. NKCC activation caused by PKA inhibition was insensitive to MEK MAPK inhibitors and to insulin but was abolished by the PKA stimulators isoproterenol and forskolin. Furthermore, pinacidil [an ATP-sensitive potassium (KATP) channel opener] or inhibition of glycolysis increased NKCC activity in the soleus muscle but not in the plantaris muscle. Preincubation of the soleus muscle with glibenclamide (a KATP channel inhibitor) prevented the NKCC activation by hyperosmolarity, PKA inhibition, pinacidil, and glycolysis inhibitors. In contrast, glibenclamide stimulated NKCC activity in the plantaris muscle. In cells stably transfected with the Kir6.2 subunit of the of KATP channel, inhibition of glycolysis activated potassium current and NKCC activity. We conclude that activation of KATP channels in slow-twitch muscle is necessary for activation of the NKCC and cell volume restoration in hyperosmotic conditions.
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Affiliation(s)
- Aidar R Gosmanov
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
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