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Straumann S, Schaft E, Noordmans H, Dankbaar J, Smits P, Zweiphenning W, Van Eijsden P, Mariani L, Van 't Klooster M, Zijlmans M. OC01 : The art of matchmaking: What is the link between findings in MRI and intraoperative electrocorticography in patients with focal epilepsy? Clin Neurophysiol 2022. [DOI: 10.1016/j.clinph.2021.11.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Gao C, Kogame N, Smits P, Tonino P, Moreno R, Choudhury A, Hofma S, Petrov I, Cequier A, Colombo A, Onuma Y, Kaul U, Zaman A, De Winter R, Serruys P. A prospective multicentre randomized all-comers trial to assess the safety and effectiveness of the ultra-thin-strut sirolimus-eluting coronary stent Supraflex: 2-year results of the TALENT trial. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.2534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background and purpose
Supraflex is a sirolimus-eluting stent with a biodegradable polymeric coating and 60um ultra-thin struts. In the TALENT study, we found the Supraflex stent was non-inferior to the Xience stent for a device-oriented composite endpoint (DOCE, defined as cardiac death, target-vessel myocardial infarction, or clinically indicated target lesion revascularisation) at 12 months in an all-comer population. Additionally, per-protocol analysis showed a significantly lower clinically indicated target lesion revascularisation (CI-TLR) in the Supraflex group than in the Xience group. We now present the 2-year follow-up results.
Methods
The TALENT study was a prospective, randomised, single-blind, multicentre study across 23 centres in Europe. Eligible participants underwent percutaneous coronary intervention in an all-comers fashion in vessels of 2.25–4.5 mm. Patients were randomized (1:1) to implantation of either Supraflex or Xience (NCT02870140).
Results
Between October 21, 2016 and July 3, 2017, 720 patients with 1046 lesions were randomly assigned to Supraflex, and 715 patients with 1030 lesions to Xience. At 24 months, DOCE had occurred in 49 patients (6.9%) in the Supraflex group and in 56 patients (7.9%) in the Xience group (absolute difference −1.0% [95% CI: −3.7 to 1.7], Plog-rank=0.491). Per-protocol analysis at 24 months showed CI-TLR occurred in 21 and 30 patients in the Supraflex and Xience, respectively (3.3% versus 4.5%, absolute difference −1.2%, [95% CI: −3.3 to 0.9], Plog-rank=0.267).
Conclusion
In an all-comer population, at 2-year follow-up, the use of Supraflex stent was at least as safe and efficacious as Xience stent. However, the significantly lower rate of CI-TLR shown in patients treated with Supraflex at 1-year was no longer retained in the 2-year results. Whether theoretical advantage of ultra-thin strut drug eluting stents Supraflex can translate into clinical benefit or not will be further elucidated through a total of 3 years of follow-up.
Funding Acknowledgement
Type of funding source: Private company. Main funding source(s): SMT
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Affiliation(s)
- C Gao
- Xijing Hospital of the Fourth Military Medical University, Xi'an, China
| | - N Kogame
- Amsterdam UMC, Amsterdam, Netherlands (The)
| | - P Smits
- Maasstad Hospital, Rotterdam, Netherlands (The)
| | - P Tonino
- Catharina Hospital, Eindhoven, Netherlands (The)
| | - R Moreno
- University Hospital La Paz, Madrid, Spain
| | - A Choudhury
- University Hospital of Wales, Cardiff, United Kingdom
| | - S Hofma
- Medical Center Leeuwarden, Leeuwarden, Netherlands (The)
| | - I Petrov
- Acibadem City Clinic Cardiovascular Center University Hospital, Sofia, Bulgaria
| | - A Cequier
- University Hospital Bellvitge, Barcelona, Spain
| | - A Colombo
- San Raffaele Scientific Institute, Milan, Italy
| | - Y Onuma
- National University of Ireland, Galway, Ireland
| | - U Kaul
- Batra Hospital and Medical Research Centre, New Delhi, India
| | - A Zaman
- University of Newcastle, Newcastle, Australia
| | | | - P.W Serruys
- National University of Ireland, Galway, Ireland
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Gao C, Kerkmeijer L, Tijssen R, Kraak R, Tijssen J, Onuma Y, Chevalier B, West N, Morice M, De Winter R, Smits P, Wykrzykowska J, Van Geuns R. Impact of diabetes mellitus on 2-year outcomes of Absorb BVS compared to Xience EES: a pooled analysis of the COMPARE-ABSORB and AIDA trial. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.2546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Background and purpose
Diabetes mellitus (DM) is associated with increased risk of cardiovascular events after percutaneous coronary intervention (PCI). To evaluate the impact of Absorb bioresorbable vascular scaffold (BVS) in patients with DM, we aimed to compare the 2-year outcomes of Absorb BVS versus 2nd generation drug eluting stents Xience (EES) by pooling diabetic patients treated with BVS or EES from two large, randomized controlled trial.
Methods
Patients with medically-treated DM and treated by Absorb BVS in the COMPARE-ABSORB and AIDA trial were pooled for analysis. The primary efficacy outcomes measure was target lesion failure (cardiac death, target-vessel myocardial infarction or target lesion revascularization), and the primary safety outcome measure was device thrombosis at 2-year follow-up.
Results
Out of a total 3515 enrolled subjects in the two trials, 913 were diabetics. Compared with the non-diabetic patients, those with DM were older, more often to have a history of hypercholesterolemia, chronic renal failure, stroke, hypertension, heart failure, peripheral vascular disease and previous PCI. At 2-years, target lesion failure occurred in 10.8% of BVS DM patients and 7.6% of EES DM patients (adjusted HR 1.43, 95% CI: 0.87–2.34, P=0.115). The 2-year rates of cardiac death (2.4% vs 1.6%, P=0.385), TV-MI (5% vs 1.6%, P=0.123) and TLR (7.8% vs 5.8%, P=0.416) showed not significant difference. The 2-year incidence of definite device thrombosis was 3.2% in Absorb BVS versus 0.7% in Xience EES (adjusted HR 4.77, 95% CI: 1.01–22.43, P=0.048).
Conclusion
This pooling of the diabetic patients from two large scale RCTs compared BVS versus 2nd generation DES, showed an increased rate of device thrombosis in BVS-treated patients at 2 years.
Funding Acknowledgement
Type of funding source: Private company. Main funding source(s): Abbott
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Affiliation(s)
- C Gao
- Xijing Hospital of the Fourth Military Medical University, Xi'an, China
| | | | | | - R Kraak
- Amsterdam UMC, Amsterdam, Netherlands (The)
| | - J Tijssen
- Amsterdam UMC, Amsterdam, Netherlands (The)
| | - Y Onuma
- National University of Ireland, Galway, Ireland
| | | | - N West
- Royal Papworth Hospital, Cambridge, United Kingdom
| | - M.C Morice
- Cardiovascular European Research Center, Massy, France
| | | | - P Smits
- Maasstad Hospital, Rotterdam, Netherlands (The)
| | | | - R.J Van Geuns
- University Medical Center St Radboud (UMCN), Nijmegen, Netherlands (The)
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Kerkmeijer L, Chao G, Tijssen R, Gori T, Kraak R, Tijssen J, Onuma Y, Chevalier B, De Winter R, Smits P, Van Geuns R, Wykrzykowska J. Two-year clinical performance of Absorb BVS compared to Xience EES in ST-segment elevation myocardial infarction: a pooled analysis of AIDA and COMPARE-ABSORB trials. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.2544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Introduction
Bioresorbable vascular scaffolds (BVS) use appears theoretically attractive in patients presenting with ST-segment elevation myocardial infarction (STEMI) as acute lesions are generally composed of soft plaques, in which optimal BVS deployment and expansion is easier to achieve. Furthermore, those patients are generally younger and would benefit longer from the promise of vascular restoration therapy.
Purpose
In this patient level pooled analysis of two clinical trials, we evaluated the clinical outcomes of Absorb BVS versus Xience everolimus-eluting stent (EES) in STEMI patients at 2-year follow-up.
Methods
We performed an individual patient-level pooled analysis of the AIDA and COMPARE-ABSORB trials in which 3515 patient were randomly assigned to Absorb BVS (n=1772) or Xience EES (n=1743). Clinical outcomes in STEMI patients were analyzed by randomized treatment assignment cumulative through 2 years. The primary efficacy outcomes measure was target lesion failure (cardiac death, target-vessel myocardial infarction or target lesion revascularization), and the primary safety outcome measure was device thrombosis at 2-year follow-up.
Results
350 (19.8%) STEMI patients were allocated to Absorb BVS versus 328 (18.8%) to Xience EES. The mean age of patient presenting with STEMI was 60 years old, 76.0% were males and 15.3% had diabetes mellitus. At 2-years target lesion failure occurred in 8.4% of BVS STEMI patients and 6.2% of EES STEMI patients (p=0.253). The 2-year rates of cardiac death (2.6% vs 1.6%, p=0.332), TV-MI (4.7% vs 2.5%) and TLR (6.8% vs 4.1%) were not significantly different. The 2-year incidence of definite device thrombosis was 4.7% in Absorb BVS versus 1.8% in Xience EES (p=0.045).
Conclusion
In the present patient-level pooled analysis of the AIDA and COMPARE-Absorb trials, BVS was associated with increased rates of device thrombosis in STEMI patients compared to Xience EES.
Funding Acknowledgement
Type of funding source: Private company. Main funding source(s): Abbott
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Affiliation(s)
- L.S.M Kerkmeijer
- Amsterdam UMC - Location Academic Medical Center, Amsterdam, Netherlands (The)
| | - G Chao
- University Medical Center St Radboud (UMCN), Nijmegen, Netherlands (The)
| | - R Tijssen
- Amsterdam UMC - Location Academic Medical Center, Amsterdam, Netherlands (The)
| | - T Gori
- University Medical Center Mainz, Mainz, Germany
| | - R.P Kraak
- Amsterdam UMC - Location Academic Medical Center, Amsterdam, Netherlands (The)
| | - J.G.P Tijssen
- Amsterdam UMC - Location Academic Medical Center, Amsterdam, Netherlands (The)
| | - Y Onuma
- Erasmus University Medical Centre, Rotterdam, Netherlands (The)
| | - B Chevalier
- Cardiovascular Institute Paris-Sud (ICPS), Massy, France
| | - R.J De Winter
- Amsterdam UMC - Location Academic Medical Center, Amsterdam, Netherlands (The)
| | - P Smits
- Maasstad Hospital, Rotterdam, Netherlands (The)
| | - R.J Van Geuns
- University Medical Center St Radboud (UMCN), Nijmegen, Netherlands (The)
| | - J.J Wykrzykowska
- Amsterdam UMC - Location Academic Medical Center, Amsterdam, Netherlands (The)
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ten Cate AJ, van de Hoek YT, Reitsma PH, Smits P, ten Cate H. Mutation Screening for Thrombophilia: Two Cases with Factor V Cambridge without Activated Protein C Resistance. Thromb Haemost 2017. [DOI: 10.1055/s-0037-1613108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Everaert B, Wykrzykowska JJ, Koolen J, van der Harst P, den Heijer P, Henriques JP, van der Schaaf R, de Smet B, Hofma SH, Diletti R, Weevers A, Hoorntje J, Smits P, van Geuns RJ. Recommendations for the use of bioresorbable vascular scaffolds in percutaneous coronary interventions : 2017 revision. Neth Heart J 2017; 25:419-428. [PMID: 28643297 PMCID: PMC5513994 DOI: 10.1007/s12471-017-1014-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND To eliminate some of the potential late limitations of permanent metallic stents, the bioresorbable coronary stents or 'bioresorbable vascular scaffolds' (BVS) have been developed. METHODS We reviewed all currently available clinical data on BVS implantation. RESULTS Since the 2015 position statement on the appropriateness of BVS in percutaneous coronary interventions, several large randomised trials have been presented. These have demonstrated that achieving adequate 1 and 2 year outcomes with these first-generation BVS is not straightforward. These first adequately powered studies in non-complex lesions showed worse results if standard implantation techniques were used for these relatively thick scaffolds. Post-hoc analyses hypothesise that outcomes similar to current drug-eluting stents are still possible if aggressive lesion preparation, adequate sizing and high-pressure postdilatation are implemented rigorously. As long as this has not been confirmed in prospective studies the usage should be restricted to experienced centres with continuous outcome monitoring. For more complex lesions, results are even more disappointing and usage should be discouraged. When developed, newer generation scaffolds with thinner struts or faster resorption rates are expected to improve outcomes. In the meantime prolonged dual antiplatelet therapy (DAPT, beyond one year) is recommended in an individualised approach for patients treated with current generation BVS. CONCLUSION The new 2017 recommendations downgrade and limit the use of the current BVS to experienced centres within dedicated registries using the updated implantation protocol and advise the prolonged usage of DAPT. In line with these recommendations the manufacturer does not supply devices to the hospitals without such registries in place.
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Affiliation(s)
- B Everaert
- Thoraxcenter, Erasmus Medical Centre, Rotterdam, The Netherlands
- Monica Hospital, Antwerp, Belgium
| | | | - J Koolen
- Catharina Hospital, Eindhoven, The Netherlands
| | - P van der Harst
- University Medical Center, University of Groningen, Groningen, The Netherlands
| | | | | | | | - B de Smet
- Meander Medical Center, Amersfoort, The Netherlands
| | - S H Hofma
- Medical Center, Leeuwarden, The Netherlands
| | - R Diletti
- Thoraxcenter, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - A Weevers
- Albert Schweitzer Hospital, Dordrecht, The Netherlands
| | - J Hoorntje
- Maastricht University Medical Center, Maastricht, The Netherlands
| | - P Smits
- Maasstad Hospital, Rotterdam, The Netherlands
| | - R J van Geuns
- Thoraxcenter, Erasmus Medical Centre, Rotterdam, The Netherlands.
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7
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Joerger M, Huitema A, Boot H, Cats A, Doodeman V, Smits P, Vainchtein L, Rosing H, Meijerman I, Zueger M, Cerny T, Beijnen J, Schellens J. Germline Tyms Genotype is Highly Predictive in Patients with Advanced Colorectal and Gastroesophageal Cancer Independent of Fluoropyrimidine Pharmacology: Results from Two Prospective Translational Studies. Ann Oncol 2014. [DOI: 10.1093/annonc/mdu358.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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8
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van Poppel P, Breedveld P, Abbink E, Schaap-Roelofs H, van Heerde W, Smits P, Lin W, Tan H, Russel F, Donders R, Tack C, Rongen G. Salvia Miltiorrhiza Water-Extract (Danshen) has No Beneficial Effect on Cardiovascular Risk Factors. Clin Ther 2014. [DOI: 10.1016/j.clinthera.2014.05.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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9
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van Poppel PCM, Gresnigt MS, Smits P, Netea MG, Tack CJ. The dipeptidyl peptidase-4 inhibitor vildagliptin does not affect ex vivo cytokine response and lymphocyte function in patients with type 2 diabetes mellitus. Diabetes Res Clin Pract 2014; 103:395-401. [PMID: 24485397 DOI: 10.1016/j.diabres.2013.12.039] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 10/30/2013] [Accepted: 12/19/2013] [Indexed: 12/17/2022]
Abstract
AIMS The enzyme dipeptidyl peptidase-4 (DPP-4) is a key player in the degradation of incretin hormones that are involved in glucose metabolism. DPP-4 is also expressed on immune cells and is associated with several immunological functions. Some studies have reported increased rates of infections in patients treated with DPP-4 inhibitors. We therefore assessed whether treatment with the DPP-4 inhibitor vildagliptin affected cytokine production and T-cell differentiation. METHODS Patients with type 2 diabetes were treated with vildagliptin or an active comparator, acarbose, for four weeks, in a randomized cross-over trial. Blood was sampled at the end of each treatment period and peripheral blood mononuclear cells were isolated and stimulated with a broad spectrum of pattern recognition receptor agonists. RESULTS Serum cytokine concentrations and ex vivo cytokine production (both monocyte and T-cell derived) did not differ during treatment with vildagliptin compared to acarbose. Similarly, ex vivo relative upregulation of mRNA transcription of T-cell lineage specific transcription factors was unaffected by vildagliptin treatment. CONCLUSIONS These data show that a four-week treatment with vildagliptin in patients with type 2 diabetes mellitus does not result in a significant modulation of cytokine responses. This observation suggests that inhibition of DDP-4 does not lead to an increased risk of infection by diminishing cytokine production.
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Affiliation(s)
- P C M van Poppel
- Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
| | - M S Gresnigt
- Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; Nijmegen Institute for Infection, Inflammation and Immunity (N4i), Nijmegen, The Netherlands
| | - P Smits
- Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; Department of Pharmacology and Toxicology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - M G Netea
- Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; Nijmegen Institute for Infection, Inflammation and Immunity (N4i), Nijmegen, The Netherlands
| | - C J Tack
- Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Ramakers B, Giamarellos-Bourboulis E, Coenen M, Kox M, Van der Hoeven J, Routsi C, Savva A, Perdios I, Diamantea F, Sinapidis D, Smits P, Riksen N, Pickkers P. Effects of the common 34C>T variant of the AMPD1 gene on immune function, multiorgan dysfunction and mortality in patients with sepsis. Crit Care 2013. [PMCID: PMC3642423 DOI: 10.1186/cc11955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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11
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Visser M, Seidell JC, Koppeschaar HP, Smits P. No Specific Effect of Fluoxetine Treatment on Fasting Glucose, Insulin, Lipid Levels, and Blood Pressure in Healthy Men with Abdominal Obesity. ACTA ACUST UNITED AC 2012; 2:152-9. [PMID: 16353616 DOI: 10.1002/j.1550-8528.1994.tb00641.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In this paper we investigated the effect of fluoxetine (60 mg/d) on serum lipids, glucose and insulin concentrations and blood pressure by means of a randomized, double-blind placebo controlled trial. Thirty-eight overweight (BMI: 26-30 kg/m2), nondiabetic, nonhypertensive men with an abdominal fat distribution (waist/hip ratio: > 0.97) received dietary advice and placebo or fluoxetine for 12 weeks. The changes in serum parameters and blood pressure in the fluoxetine treated group were not different from the placebo treated group, despite a significantly larger weight loss in the fluoxetine group. In both groups serum total-cholesterol concentrations, serum LDL-cholesterol concentrations and the HDL/LDL ratio were significantly improved after treatment. Reductions in fasting glucose concentration and systolic blood pressure were only significant in the placebo group. A reduction of serum triglycerides and an increase of HDL-cholesterol were found in the fluoxetine treated group. In the total study population the changes in serum lipids seemed to be more strongly related to the change in total body fat or subcutaneous abdominal fat (assessed by MRI) compared to the change in visceral fat. The improvement of most of the serum lipids was related to the change in total body fat independent of the mechanism for attaining this fat loss. Our results indicate that fluoxetine treatment has no specific effect beyond that expected for weight loss on serum lipid, glucose and insulin concentrations, and blood pressure in overweight men.
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Affiliation(s)
- M Visser
- Department of Human Nutrition, Wageningen Agricultural University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
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12
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Schouwenberg BJJW, Smits P, Tack CJ, de Galan BE. The effect of antecedent hypoglycaemia on β₂-adrenergic sensitivity in healthy participants with the Arg16Gly polymorphism of the β₂-adrenergic receptor. Diabetologia 2011; 54:1212-8. [PMID: 21298412 PMCID: PMC3071931 DOI: 10.1007/s00125-011-2062-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Accepted: 01/10/2011] [Indexed: 11/20/2022]
Abstract
AIMS/HYPOTHESIS Homozygosity for glycine at codon 16 (GlyGly) of the β(2)-adrenergic receptor may alter receptor sensitivity upon chronic stimulation and has been implicated in the pathogenesis of hypoglycaemia unawareness. We compared the effect of antecedent hypoglycaemia on β(2)-adrenergic receptor sensitivity between GlyGly participants and those with arginine 16 homozygosity (ArgArg) for the β(2)-adrenergic receptor. METHODS We enrolled 16 healthy participants, who were either GlyGly (n = 8) or ArgArg (n = 8). They participated randomly in two 2 day experiments. Day 1 consisted of two 2-h hyperinsulinaemic hypoglycaemic (2.8 mmol/l) or euglycaemic (4.8 mmol/l) glucose clamps. On day 2, we measured the forearm vasodilator response to the β(2)-adrenergic receptor agonist salbutamol and the dose of isoprenaline required to increase the heart rate by 25 bpm (IC(25)). RESULTS The vasodilator response to salbutamol tended to be greater after antecedent hypoglycaemia than after euglycaemia (p = 0.078), consistent with increased β(2)-adrenergic receptor sensitivity. This effect was driven by a significant increase in β(2)-adrenergic receptor sensitivity following hypoglycaemia compared with euglycaemia in ArgArg participants (p = 0.019), whereas no such effect was observed in the GlyGly participants. Antecedent hypoglycaemia tended to decrease the IC(25) in ArgArg participants, whereas the reverse occurred in the GlyGly participants (GlyGly vs ArgArg group p = 0.047). CONCLUSION/INTERPRETATION Antecedent hypoglycaemia did not affect β(2)-adrenergic receptor sensitivity in healthy GlyGly participants, but increased it in ArgArg participants. If these results also hold for participants with type 1 diabetes, such an increase in β(2)-adrenergic receptor sensitivity may potentially reduce the risk of repeated hypoglycaemia and the subsequent development of hypoglycaemia unawareness in ArgArg diabetic participants. TRIAL REGISTRATION ClinicalTrials.gov NCT00160056.
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Affiliation(s)
- B J J W Schouwenberg
- Department of Pharmacology-Toxicology 149, Radboud University Nijmegen Medical Centre, Geert Grooteplein 21, PO Box 9101, 6500HB Nijmegen, the Netherlands.
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Rennings AJ, Russel FG, Li Y, Deen PM, Masereeuw R, Tack CJ, Smits P. Preserved Response to Diuretics in Rosiglitazone-Treated Subjects With Insulin Resistance: A Randomized Double-Blind Placebo-Controlled Crossover Study. Clin Pharmacol Ther 2011; 89:587-94. [DOI: 10.1038/clpt.2010.360] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ramakers B, Riksen NP, Stal TH, Heemskerk S, Van den Broek P, Van der Hoeven JG, Smits P, Pickkers P. Dipyridamole modulates the innate immune response during human endotoxemia. Crit Care 2011. [PMCID: PMC3066940 DOI: 10.1186/cc9686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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15
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Smits P, Rodenburg RJ, Smeitink JAM, van den Heuvel LP. Sequence variants in four candidate genes (NIPSNAP1, GBAS, CHCHD1 and METT11D1) in patients with combined oxidative phosphorylation system deficiencies. J Inherit Metab Dis 2010; 33 Suppl 3:S13-9. [PMID: 24137763 DOI: 10.1007/s10545-009-0968-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The oxidative phosphorylation (OXPHOS) system, comprising five enzyme complexes, is located in the inner membrane of mitochondria and is the final biochemical pathway in oxidative ATP production. Defects in this energy-generating system can cause a wide range of clinical symptoms; these diseases are often progressive and multisystemic. Numerous genes have been implicated in OXPHOS deficiencies and many mutations have been described. However, in a substantial number of patients with decreased enzyme activities of two or more OXPHOS complexes, no mutations in the mitochondrial DNA or in nuclear genes known to be involved in these disorders have been found. In this study, four nuclear candidate genes--NIPSNAP1, GBAS, CHCHD1 and METT11D1--were screened for mutations in 22 patients with a combined enzymatic deficiency of primarily the OXPHOS complexes I, III and IV to determine whether a mutation in one of these genes could explain the mitochondrial disorder. For each variant not yet reported as a polymorphism, 100 control samples were screened for the presence of the variant. This way we identified 14 new polymorphisms and 2 presumably non-pathogenic mutations. No mutations were found that could explain the mitochondrial disorder in the patients investigated in this study. Therefore, the genetic defect in these patients must be located in other nuclear genes involved in mtDNA maintenance, transcription or translation, in import, processing or degradation of nuclear encoded mitochondrial proteins, or in assembly of the OXPHOS system.
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Affiliation(s)
- P Smits
- Department of Pediatrics, Nijmegen Centre for Mitochondrial Disorders, Radboud University Nijmegen Medical Centre, Geert Grooteplein 10, PO Box 9101, 6500 HB Nijmegen, The Netherlands
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Gomes ME, El Messaoudi S, Lenders JWM, Bellersen L, Verheugt FWA, Smits P, Tack CJ. High dose ascorbic acid does not reverse central sympathetic overactivity in chronic heart failure. J Clin Pharm Ther 2010; 36:546-52. [PMID: 21916906 DOI: 10.1111/j.1365-2710.2010.01205.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE The increased central sympathetic activity typically associated with chronic heart failure (CHF) is probably mediated by formation of reactive oxygen species (ROS) in the brain. Our objective was to undertake a trial to test our hypothesis that administration of the well-known antioxidant and ROS scavenger ascorbic acid, would reverse or reduce the sympathetic overactivity in CHF patients. METHODS In a prospective, randomized, placebo-controlled, double-blind, cross-over trial, 11 CHF patients were treated with ascorbic acid 2 g/day or placebo for 3 days. At the end of each treatment period, sympathetic nervous system activity was measured by microneurography for direct muscle sympathetic nerve activity (MSNA) recording, analysis of heart rate variability (HRV) and measurement of plasma norepinephrine concentrations. RESULTS During ascorbic acid administration, plasma vitamin C levels were higher than during placebo (74·9 ± 6·0 μmol/L vs. 54·8 ± 4·6 μmol/L, P = 0·03). Ascorbic acid had no effect on sympathetic activity: MSNA (ascorbic acid: 66·8 ± 3·3 vs. placebo 66·9 ± 3·2 bursts/100 beats, P = 0·98). In addition, HRV and plasma norepinephrine levels did not differ. WHAT IS NEW AND CONCLUSION Short-term administration of the antioxidant ascorbic acid in CHF patients does not reverse the increased sympathetic activity as measured by microneurography, HRV and plasma norepinephrine levels. The use of higher oral dosages seems not feasible due to accompanying side effects.
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Affiliation(s)
- M E Gomes
- Department of Internal Medicine Department of Cardiology Department of Pharmacology Toxicology, University Medical Center Nijmegen, Nijmegen, The Netherlands
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Rennings AJ, Smits P, Stewart MW, Tack CJ. Autonomic neuropathy predisposes to rosiglitazone-induced vascular leakage in insulin-treated patients with type 2 diabetes: a randomised, controlled trial on thiazolidinedione-induced vascular leakage. Diabetologia 2010; 53:1856-66. [PMID: 20499046 PMCID: PMC2910895 DOI: 10.1007/s00125-010-1787-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2010] [Accepted: 04/16/2010] [Indexed: 12/14/2022]
Abstract
AIMS/HYPOTHESIS The mechanism of fluid-related complications caused by thiazolidinedione derivatives is unclear. One potential mechanism is thiazolidinedione-induced arterial vasodilatation, which results in vascular leakage and a fall in blood pressure, normally counterbalanced by sympathetic activation and subsequent renal fluid retention. We hypothesised that thiazolidinedione-induced vascular leakage will be particularly prominent in patients with autonomic neuropathy. METHODS We conducted a randomised, double-blind, placebo-controlled, parallel study in 40 patients with type 2 diabetes on insulin treatment recruited from a university medical centre. The randomisation was performed by a central office using a randomisation schedule. Both treatment groups, placebo (n = 21) and rosiglitazone (n = 19), were stratified for sex and level of autonomic neuropathy as assessed by Ewing score (<2.5 or >or=2.5). We investigated the effects of 16 weeks of treatment with rosiglitazone 4 mg twice daily on vascular leakage (transcapillary escape rate of albumin, TERalb), body weight, extracellular volume and plasma volume. RESULTS Thirty-nine patients were included in the analysis. In patients with high Ewing scores (n = 16), rosiglitazone increased TERalb significantly (DeltaTERalb: rosiglitazone +2.43 +/- 0.45%/h, placebo -0.11 +/- 0.15%/h, p = 0.002), while rosiglitazone had no effect in the patients with low Ewing scores (n = 23). Rosiglitazone-induced increases in TERalb and Ewing score at baseline were correlated (r = 0.65, p = 0.02). There was no correlation between Ewing score and rosiglitazone-induced changes in fluid variables. One subject was withdrawn from the study because of atrial fibrillation. CONCLUSIONS/INTERPRETATION Rosiglitazone may increase vascular leakage in insulin-treated patients with type 2 diabetes with autonomic neuropathy. Autonomic neuropathy did not exaggerate rosiglitazone-induced fluid retention. Therefore, autonomic neuropathy should be considered as a risk factor for thiazolidinedione-induced oedema, not for thiazolidinedione-induced fluid retention. TRIAL REGISTRATION ClinicalTrials.gov NCT00422955. FUNDING GlaxoSmithKline.
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Affiliation(s)
- A J Rennings
- Department of Pharmacology-Toxicology 149, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands.
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Kooijman M, Rongen GA, Smits P, van Kuppevelt HJM, Hopman MTE. The role of the alpha-adrenergic receptor in the leg vasoconstrictor response to orthostatic stress. Acta Physiol (Oxf) 2009; 195:357-66. [PMID: 18801054 DOI: 10.1111/j.1748-1716.2008.01904.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM The prompt increase in peripheral vascular resistance, mediated by sympathetic alpha-adrenergic stimulation, is believed to be the key event in blood pressure control during postural stress. However, despite the absence of central sympathetic control of the leg vasculature, postural leg vasoconstriction is preserved in spinal cord-injured individuals (SCI). This study aimed at assessing the contribution of both central and local sympathetically induced alpha-adrenergic leg vasoconstriction to head-up tilt (HUT) by including healthy individuals and SCI, who lack central sympathetic baroreflex control over the leg vascular bed. METHODS In 10 controls and nine SCI the femoral artery was cannulated for drug infusion. Upper leg blood flow (LBF) was measured bilaterally using venous occlusion strain gauge plethysmography before and during 30 degrees HUT throughout intra-arterial infusion of saline or the non-selective alpha-adrenergic receptor antagonist phentolamine respectively. Additionally, in six controls the leg vascular response to the cold pressor test was assessed during continued infusion of phentolamine, in order to confirm complete alpha-adrenergic blockade by phentolamine. RESULTS During infusion of phentolamine HUT still caused vasoconstriction in both groups: leg vascular resistance (mean arterial pressure/LBF) increased by 10 +/- 2 AU (compared with 12 +/- 2 AU during saline infusion), and 13 +/- 3 AU (compared with 7 +/- 3 AU during saline infusion) in controls and SCI respectively. CONCLUSION Effective alpha-adrenergic blockade did not reduce HUT-induced vasoconstriction, regardless of intact baroreflex control of the leg vasculature. Apparently, redundant mechanisms compensate for the absence of sympathetic alpha-adrenoceptor leg vasoconstriction in response to postural stress.
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Affiliation(s)
- M Kooijman
- Department of Physiology and Institute of Fundamental and Clinical Movement Sciences, Radboud University Nijmegen Medical Centre, Geert Grooteplein Noord 21, Nijmegen, The Netherlands
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de Wijkerslooth LRH, Koch BCP, Malingré MM, Smits P, Bartelink AKM. [Acute caffeine intoxication after intake of 'herbal energy capsules']. Ned Tijdschr Geneeskd 2008; 152:2312. [PMID: 19009885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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Ramakers B, Pickkers P, Deussen A, Rongen G, Broek P, Hoeven J, Smits P, Riksen N. Measurement of the Endogenous Adenosine Concentration in Humans In Vivo: Methodological Considerations. Curr Drug Metab 2008; 9:679-85. [DOI: 10.2174/138920008786049249] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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22
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Boon H, Bosselaar M, Praet SFE, Blaak EE, Saris WHM, Wagenmakers AJM, McGee SL, Tack CJ, Smits P, Hargreaves M, van Loon LJC. Intravenous AICAR administration reduces hepatic glucose output and inhibits whole body lipolysis in type 2 diabetic patients. Diabetologia 2008; 51:1893-900. [PMID: 18709353 DOI: 10.1007/s00125-008-1108-7] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2008] [Accepted: 07/02/2008] [Indexed: 11/26/2022]
Abstract
AIMS/HYPOTHESIS The 5'-AMP-activated protein kinase (AMPK) pathway is intact in type 2 diabetic patients and is seen as a target for diabetes treatment. In this study, we aimed to assess the impact of the AMPK activator 5-aminoimidazole-4-carboxamide riboside (AICAR) on both glucose and fatty acid metabolism in vivo in type 2 diabetic patients. METHODS Stable isotope methodology and blood and muscle biopsy sampling were applied to assess blood glucose and fatty acid kinetics following continuous i.v. infusion of AICAR (0.75 mg kg(-1) min(-1)) and/or NaCl (0.9%) in ten male type 2 diabetic patients (age 64 +/- 2 years; BMI 28 +/- 1 kg/m(2)). RESULTS Plasma glucose rate of appearance (R (a)) was reduced following AICAR administration, while plasma glucose rate of disappearance (R (d)) was similar in the AICAR and control test. Consequently, blood glucose disposal (R (d) expressed as a percentage of R (a)) was increased following AICAR infusion (p < 0.001). Accordingly, a greater decline in plasma glucose concentration was observed following AICAR infusion (p < 0.001). Plasma NEFA R (a) and R (d) were both significantly reduced in response to AICAR infusion, and were accompanied by a significant decline in plasma NEFA concentration. Although AMPK phosphorylation in skeletal muscle was not increased, we observed a significant increase in acetyl-CoA carboxylase phosphorylation (p < 0.001). CONCLUSIONS/INTERPRETATION The i.v. administration of AICAR reduces hepatic glucose output, thereby lowering blood glucose concentrations in vivo in type 2 diabetic patients. Furthermore, AICAR administration stimulates hepatic fatty acid oxidation and/or inhibits whole body lipolysis, thereby reducing plasma NEFA concentration.
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Affiliation(s)
- H Boon
- Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht, Maastricht University, Maastricht, the Netherlands.
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de Wijkerslooth LRH, Koch BCP, Malingré MM, Smits P, Bartelink AKM. Life-threatening hypokalaemia and lactate accumulation after autointoxication with Stacker 2, a 'powerful slimming agent'. Br J Clin Pharmacol 2008; 66:728-31. [PMID: 18823307 DOI: 10.1111/j.1365-2125.2008.03279.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Thijssen DHJ, Kooijman M, de Groot PCE, Bleeker MWP, Smits P, Green DJ, Hopman MTE. Endothelium-dependent and -independent vasodilation of the superficial femoral artery in spinal cord-injured subjects. J Appl Physiol (1985) 2008; 104:1387-93. [PMID: 18309094 DOI: 10.1152/japplphysiol.01039.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Extreme inactivity of the legs in spinal cord-injured (SCI) individuals does not result in an impairment of the superficial femoral artery flow-mediated dilation (FMD). To gain insight into the underlying mechanism, the present study examined nitric oxide (NO) responsiveness of vascular smooth muscles in controls and SCI subjects. In eight healthy men (34 +/- 13 yr) and six SCI subjects (37 +/- 10 yr), superficial femoral artery FMD response was assessed by echo Doppler. Subsequently, infusion of incremental dosages of sodium nitroprusside (SNP) was used to assess NO responsiveness. Peak diameter was examined on a second day after 13 min of arterial occlusion in combination with sublingual administration of nitroglycerine. Resting and peak superficial femoral artery diameter in SCI subjects were smaller than in controls (P < 0.001). The FMD response in controls (4.2 +/- 0.9%) was lower than in SCI subjects (8.2 +/- 0.9%, P < 0.001), but not after correcting for area under the curve for shear rate (P = 0.35). When expressed as relative change from baseline, SCI subjects demonstrate a significantly larger diameter increase compared with controls at each dose of SNP. However, when expressed as a relative increase within the range of diameter changes [baseline (0%) - peak diameter (100%)], both groups demonstrate similar changes in response to SNP. Changes in diameter during SNP infusion and FMD response are larger in SCI subjects compared with controls. When these results are corrected, superficial femoral artery FMD and NO sensitivity in SCI subjects are not different from those in controls. This illustrates the importance of appropriate data presentation and suggests that, subsequent to structural inward remodeling of conduit arteries as a consequence of extreme physical inactivity, arterial function is normalized.
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Affiliation(s)
- D H J Thijssen
- Department of Physiology, Radboud University Nijmegen Medical Centre, Geert Grooteplein-noord 21, Nijmegen, The Netherlands
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Kooijman M, Thijssen DHJ, de Groot PCE, Bleeker MWP, van Kuppevelt HJM, Green DJ, Rongen GA, Smits P, Hopman MTE. Flow-mediated dilatation in the superficial femoral artery is nitric oxide mediated in humans. J Physiol 2007; 586:1137-45. [PMID: 18096601 DOI: 10.1113/jphysiol.2007.145722] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Flow-mediated dilatation (FMD) of the brachial and radial arteries is an important research tool for assessment of endothelial function in vivo, and is nitric oxide (NO) dependent. The leg skeletal muscle vascular bed is an important territory for studies in exercise physiology. However, the role of endothelial NO in the FMD response of lower limb arteries has never been investigated. The purpose of this study was to examine the contribution of NO to FMD in the superficial femoral artery in healthy subjects. Since physical inactivity may affect endothelial function, and therefore NO availability, spinal cord-injured (SCI) individuals were included as a model of extreme deconditioning. In eight healthy men (34 +/- 13 years) and six SCI individuals (37 +/- 10 years), the 5 min FMD response in the superficial femoral artery was assessed by echo-Doppler, both during infusion of saline and during infusion of the NO synthase blocker N(G)-monomethyl-L-arginine (L-NMMA). In a subset of the controls (n = 6), the 10 min FMD response was also examined using the same procedure. The 5 min FMD response in controls (4.2 +/- 0.3%) was significantly diminished during L-NMMA infusion (1.0 +/- 0.2%, P < 0.001). In SCI, L-NMMA also significantly decreased the FMD response (from 8.2 +/- 0.4% during saline to 2.4 +/- 0.5% during L-NMMA infusion). The hyperaemic flow response during the first 45 s after cuff deflation was lower in both groups during infusion of L-NMMA, but the effect of L-NMMA on FMD persisted in both groups after correction for the shear stress stimulus. The 10 min FMD was not affected by L-NMMA (saline: 5.4 +/- 1.6%, L-NMMA: 5.6 +/- 1.5%). Superficial femoral artery FMD in response to distal arterial occlusion for a period of 5 min is predominantly mediated by NO in healthy men and in the extremely deconditioned legs of SCI individuals.
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Affiliation(s)
- M Kooijman
- Department of Physiology, Radboud University Nijmegen Medical Centre, the Netherlands
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Abstract
The inner surrounding of arterial vessels, the endothelium, is optimally located to detect changes in blood characteristics or blood flow that may result from changes in physical activity or from diseases. In response to physical stimuli, the endothelium varies its release of circulating vasoactive substances and serves as a source of local and systemic endothelium-derived dilator and vasoconstrictor factors. Endothelial dysfunction is one of the earliest markers of vascular abnormalities observed in cardiovascular disease and ageing. Exercise training is an efficient therapeutic strategy to improve endothelial function. Traditionally, studies on endothelial dysfunction and physical (in)activity-related effects on vascular adaptations are primarily focused on vasodilator substances (i.e. nitric oxide). One may suggest that augmentation of vasoconstrictor pathways (such as endothelin-1 and angiotensin II) contributes to the endothelial dysfunction observed after physical inactivity. Moreover, these pathways may also explain the exercise-induced beneficial cardiovascular adaptations. This review summarizes the current knowledge on the effects of physical (in)activity on several endothelium-derived vasoconstrictor substances.
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Affiliation(s)
- D H J Thijssen
- Department of Physiology, Radboud University Nijmegen Medical Centre, Geert Grooteplein-noord 21, 6525 EZ Nijmegen, the Netherlands.
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Kooijman M, de Hoog M, Rongen GA, van Kuppevelt HJM, Smits P, Hopman MTE. Local vasoconstriction in spinal cord-injured and able-bodied individuals. J Appl Physiol (1985) 2007; 103:1070-7. [PMID: 17626837 DOI: 10.1152/japplphysiol.00053.2007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Local vasoconstriction plays an important role in maintaining blood pressure in spinal cord-injured individuals (SCI). We aimed to unravel the mechanisms of local vasoconstriction [venoarteriolar reflex (VAR) and myogenic response] using both limb dependency and cuff inflation in SCI and compare these with control subjects. Limb blood flow was measured in 11 male SCI (age: 24–55 yr old) and 9 male controls (age: 23–56 yr old) using venous occlusion plethysmography in forearm and calf during three levels of 1) limb dependency, and 2) cuff inflation. During limb dependency, vasoconstriction relies on both the VAR and the myogenic response. During cuff inflation, the decrease in blood flow is caused by the VAR and by a decrease in arteriovenous pressure difference, whereas the myogenic response does not play a role. At the highest level of leg dependency, the percent increase in calf vascular resistance (mean arterial pressure/calf blood flow) was more pronounced in SCI than in controls (SCI 186 ± 53%; controls 51 ± 17%; P = 0.032). In contrast, during cuff inflation, no differences were found between SCI and controls (SCI 17 ± 17%; controls 14 ± 10%). Percent changes in forearm vascular resistance in response to either forearm dependency or forearm cuff inflation were equal in both groups. Thus local vasoconstriction during dependency of the paralyzed leg in SCI is enhanced. The contribution of the VAR to local vasoconstriction does not differ between the groups, since no differences between groups existed for cuff inflation. Therefore, the augmented local vasoconstriction in SCI during leg dependency relies, most likely, on the myogenic response.
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Affiliation(s)
- M Kooijman
- Department of Physiology, Radboud University Nijmegen Medical Centre, Geert Grooteplein Noord 21, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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Abstract
AIM Because age-related changes in the large conduit arteries (increased wall thickness, and attenuated arterial compliance and endothelial function) are associated with cardiovascular pathology, prevention is of paramount importance. The effects of endurance training (i.e. walking or cycling) in older humans are assessed in cross-sectional studies, examining the brachial and carotid arteries (supplying non-trained areas). The purpose of this study was to assess the effects of 8-week endurance training in older men on conduit artery characteristics in the trained and non-trained vascular beds. METHODS In eight healthy sedentary older men (70 +/- 3 years), characteristics of the large conduit arteries [common femoral (CFA), superficial femoral (SFA), carotid (CA), and brachial artery (BA)] were measured before and after 8-week cycling training. Functional [arterial compliance and flow-mediated dilation (FMD)] and structural (diameter and intima-media thickness) conduit artery properties were measured using echo-Doppler. Peak blood flow, representing structural peripheral adaptations, was measured using venous occlusion plethysmography. RESULTS After training, peak leg blood flow was increased (P < 0.01) and baseline diameter and flow were increased in the CFA (P < 0.05). Cycling training enhanced arterial compliance of the SFA (P = 0.03), but did not affect the FMD (P = 0.32) or the intima-media thickness of the SFA. Exercise training did not alter characteristics of the BA or CA. CONCLUSION Eight weeks of endurance training in older men altered functional and structural characteristics of the lower extremity vasculature, whereas no changes are reported for the conduit arteries in the non-trained areas (BA or in the CA).
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Affiliation(s)
- D H J Thijssen
- Department of Physiology, Institute of Fundamental and Clinical Movement science, Radboud University Nijmegen Medical Centre, The Netherlands
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van Broekhoven F, Bäckström T, van Luijtelaar G, Buitelaar JK, Smits P, Verkes RJ. Effects of allopregnanolone on sedation in men, and in women on oral contraceptives. Psychoneuroendocrinology 2007; 32:555-64. [PMID: 17470385 DOI: 10.1016/j.psyneuen.2007.03.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2006] [Revised: 03/18/2007] [Accepted: 03/19/2007] [Indexed: 10/23/2022]
Abstract
Allopregnanolone is a known GABA(A) receptor agonist not previously given to men, or to women using oral contraceptives (OC). The effects of metabolites of sex hormones on the GABA(A) receptor are different between men and women. OC are known to change GABA(A) receptor subunit composition. These factors might play a role in the differential effect of allopregnanolone in men and women, and in women with or without OC. To study the sedative effect of and sensitivity to allopregnanolone in men and in women with OC, nine healthy men (mean age 24.6 years) and nine healthy women on OC (mean age 21.8 years) were given three, increasing, intravenous dosages (0.015, 0.03, and 0.045 mg/kg) of allopregnanolone. Saccadic eye velocity (SEV), subjective ratings, and electroencephalography (EEG) were used to evaluate the response to allopregnanolone. Repeated blood samples for analyses of serum allopregnanolone levels were drawn throughout the study day. Allopregnanolone decreased SEV more in women than in men, and increased subjective ratings of 'sedation'. The results in women on OC are similar to earlier results in women without OC. Subjective ratings of 'contentedness' decreased in men but increased in women. Serum levels of allopregnanolone were more highly increased in men compared to women. Other pharmacokinetic parameters were not different between sexes. On the EEG, beta power increased in men. In conclusion, men and women on OC reacted differently to allopregnanolone.
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Affiliation(s)
- F van Broekhoven
- Department of Psychiatry, Unit for Clinical Psychopharmacology and Neuropsychiatry, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
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Meijer P, Riksen N, Scheffer GJ, Smits P, Rongen GA. Dipyridamole enhances ischemia-induced reactive hyperemia by increased adenosine receptor stimulation. Br J Clin Pharmacol 2007. [DOI: 10.1111/j.1365-2125.2007.02886_5.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Riksen NP, Franke B, Oyen WJG, van den Broek P, Boerman OC, Smits P, Rongen GA. Augmented hyperemia and reduced tissue injury in response to ischemia in subjects with the 34C > T variant of the AMPD1 gene. Br J Clin Pharmacol 2007. [DOI: 10.1111/j.1365-2125.2007.02886_6.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Husada G, Kouwenhoven E, Damste-Sinnighe H, Vellinga K, Smits P. CLC038 ORAL CT-guided wire localization of pulmonary lesions prior to thoracoscopic resection. Lung Cancer 2007. [DOI: 10.1016/s0169-5002(07)70038-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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van Moerkerk HTB, Uijtdewilligen PJE, Smits P, Daamen WF, van Kuppevelt TH. Preparation of a growth factor gradient in porous collagen scaffolds and its effect on cell growth proliferation. J Control Release 2006; 116:e87-8. [PMID: 17718988 DOI: 10.1016/j.jconrel.2006.09.064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- H T B van Moerkerk
- Dept. of Biochemistry 280, NCMLS, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Abstract
BACKGROUND According to the 'haemodynamic hypothesis', increased tissue perfusion predisposes to microangiopathy in diabetic patients. We hypothesized that the typical haemodynamic changes underlying the increased tissue perfusion can be explained by a decreased sympathetic nerve activity caused by chronic hyperglycaemia. In this study we investigated sympathetic activity in patients with uncomplicated type 1 diabetes mellitus (DM). MATERIALS AND METHODS In 15 DM patients (DM duration 6.3 +/- 3.8 year; HbA1c 7.9 +/- 1.3%) and 16 age- and sex-matched healthy volunteers (Control), sympathetic nervous system activity was measured at rest (baseline) and during sympathoneural stimulation (lower body negative pressure (LBNP)) by means of interstitial and plasma noradrenaline (NA) sampling and power spectral analysis. Muscle sympathetic nerve activity (MSNA) was measured before (baseline) and during a cold pressure test. Forearm blood flow was measured during forearm vascular alpha- and beta-adrenergic receptor blockade. RESULTS At baseline, forearm vascular resistance (FVR), plasma NA concentrations, MSNA and heart rate variability were similar in both groups. LBNP-induced vasoconstriction was significantly attenuated in the DM group compared with the Control group (DeltaFVR: 12 +/- 4 vs. 19 +/- 3 arbitrary units, P < 0.05). The responses of plasma NA and heart rate variability did not differ. CONCLUSIONS Baseline FVR and sympathetic nerve activity are normal in patients with uncomplicated type 1 diabetes. However, the forearm vasoconstrictor response to sympathetic stimulation is attenuated, which cannot be attributed to an impaired sympathetic responsiveness.
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Affiliation(s)
- P J van Gurp
- Division of General Internal Medicine, Department of Medicine, Radboud University Nijmegen Medical Centre, the Netherlands.
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de Galan BE, Schouwenberg BJJW, Tack CJ, Smits P. Pathophysiology and management of recurrent hypoglycaemia and hypoglycaemia unawareness in diabetes. Neth J Med 2006; 64:269-79. [PMID: 16990690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Iatrogenic hypoglycaemia is a well-known complication of insulin therapy in patients with diabetes mellitus and a limiting factor for glycaemic control. In a setting of endogenous insulin deficiency (type 1 and advanced type 2 diabetes), one episode of hypoglycaemia reduces both counterregulatory hormone responses to and subjective awareness of subsequent hypoglycaemia, thus impairing physiological defences against hypoglycaemia. This phenomenon may lead to a vicious cycle of recurrent hypoglycaemia and glucose counterregulatory failure, of which hypoglycaemia unawareness (i.e. the inability to perceive symptoms of hypoglycaemia) is the clinical representative. The underlying mechanism of hypoglycaemia-induced counterregulatory failure has not yet been disclosed. Patients with clinical hypoglycaemia unawareness are at high risk of severe hypoglycaemia that requires third-party assistance. Management options include avoidance of hypoglycaemic events and optimisation of insulin therapy to limit deterioration of glycaemic control associated with hypoglycaemia avoidance. Several counterregulatory-stimulating agents have been found to improve hypoglycaemic awareness in small clinical trials, but none have been tested in sufficiently large randomised studies to justify their use in daily practice. More research is required to elucidate the pathogenesis of counterregulatory failure and to develop adequate treatment strategies.
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Affiliation(s)
- B E de Galan
- Department of Medicine, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB, Nijmegen, the Netherlands.
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Smits P. Outcome of coronary revascularisation in diabetes. Neth J Med 2006; 64:265-6. [PMID: 16990688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
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Drenth JPH, Smits P, Thien T, Stalenhoef AFH. The case for case reports in the Netherlands Journal of Medicine. Neth J Med 2006; 64:262-4. [PMID: 16929093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Affiliation(s)
- J P H Drenth
- Department of Gastroenterology, Radbound University Nijmengen Medical Center, the Netherlands.
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de Hoon JNJM, Smits P, Troost J, Struijker-Boudier HAJ, Van Bortel LMAB. Forearm vascular response to nitric oxide and calcitonin gene-related peptide: comparison between migraine patients and control subjects. Cephalalgia 2006; 26:56-63. [PMID: 16396667 DOI: 10.1111/j.1468-2982.2005.00993.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The forearm vascular response to nitric oxide (NO) and calcitonin gene-related peptide (CGRP) was investigated in 10 migraine patients and 10 matched control subjects. Changes in forearm blood flow (FBF) during intrabrachial infusion of: (i) serotonin (releasing endogenous NO), (ii) sodium nitroprusside (SNP, exogenous NO-donor), and (iii) CGRP were measured using venous occlusion plethysmography. Flow-mediated dilation (FMD) of the brachial artery, a measure for the endogenous release of NO reactive to occlusion, was measured using ultrasound and expressed as percentage change vs. baseline diameter. FBF ratio (i.e. FBF in the infused over the control arm) at baseline (1.1 +/- 0.1) did not differ between both populations. Serotonin, SNP and CGRP induced a dose-dependent increase (P < 0.001) in FBF ratio in controls (to 2.8 +/- 0.3, 6.7 +/- 1.4 and 6.9 +/- 1.2 at the highest dose, respectively) and migraineurs (2.5 +/- 0.4, 5.6 +/- 0.8 and 6.5 +/- 1.3, respectively); these ratios did not differ between both groups. FMD was comparable in control subjects (5.8 +/- 1%) and migraine patients (5.2 +/- 1%). Based on the forearm vascular response to NO and CGRP, migraine patients do not display generalized changes in vascular function.
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Affiliation(s)
- J N J M de Hoon
- Centre for Clinical Pharmacology, University Hospital Gasthuisberg (K.U.Leuven), Leuven, Belgium
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Tack CJJ, Smits P. Thiazolidinedione derivatives in type 2 diabetes mellitus. Neth J Med 2006; 64:166-74. [PMID: 16788214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
In Europe, the thiazolidinedione derivatives pioglitazone and rosiglitazone have been approved for the treatment of type 2 diabetes mellitus either as monotherapy for patients with intolerance or contraindications to metformin or in combination therapy. This class of drugs seems particularly suited for obese patients, but is currently not considered as a first choice for monotherapy. The efficacy with respect to blood glucose lowering is comparable with sulphonylurea (SU) derivatives and with metformin. Long-term data with respect to efficacy and side effects are still limited.
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Affiliation(s)
- C J J Tack
- Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
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van Eijk L, Nooteboom A, Hendriks T, Sprong T, Netea M, Smits P, van der Hoeven J, Pickkers P. Crit Care 2006; 10:P149. [DOI: 10.1186/cc4496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Dorresteijn M, Draisma A, Smits P, van der Hoeven J, Pickkers P. Crit Care 2006; 10:P148. [DOI: 10.1186/cc4495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Drenth JPH, Smits P, Thien T, Stalenhoef AFH. The Netherlands Journal of Medicine's hit list: best cited articles in 2003. Neth J Med 2005; 63:418-20. [PMID: 16397309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
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Abstract
BACKGROUND Animal studies suggest that the anti-inflammatory effect of methotrexate (MTX) is mediated by increased adenosine concentrations. OBJECTIVE To assess the effect of MTX on the vasodilator effects of adenosine and the nucleoside uptake inhibitor, dipyridamole, in humans in vivo as a marker for changes in adenosine kinetics. METHODS Ten patients with active arthritis were treated with MTX (15 mg/week). Measurements were performed before and after 12 weeks of treatment. At these time points, the activity of adenosine deaminase was measured in isolated lymphocytes, and forearm blood flow (FBF) was determined by venous occlusion plethysmography during administration of adenosine and dipyridamole into the brachial artery. RESULTS The Vmax of adenosine deaminase in lymphocytes was reduced by MTX treatment (p<0.05). MTX significantly enhanced vasodilator response to adenosine (0.5 and 1.5 microg/min/dl of forearm tissue; mean (SE) FBF ratio increased from 1.2 (0.2) to 1.4 (0.2) and 2.2 (0.2) ml/dl/min, respectively, before and from 1.3 (0.1) to 1.8 (0.2) and 3.2 (0.5) ml/dl/min during MTX treatment; p<0.05). Also, dipyridamole-induced vasodilatation (30 and 100 microg/min/dl) was enhanced by MTX (FBF ratio increased from 1.2 (0.2) to 1.5 (0.3) and 1.8 (0.2), respectively, before and from 1.3 (0.1) to 1.8 (0.2) and 2.4 (0.4) during MTX treatment; p<0.05). CONCLUSIONS MTX treatment inhibits deamination of adenosine and potentiates adenosine-induced vasodilatation. Also dipyridamole-induced vasodilatation is enhanced by MTX treatment, suggesting an increased extracellular formation of adenosine. These effects on the adenosine kinetics in humans may contribute to the therapeutic efficacy of MTX.
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Affiliation(s)
- N P Riksen
- Department of Pharmacology-Toxicology 149, Radboud University Nijmegen Medical Centre, Geert Grooteplein 21, 6525 EZ Nijmegen, The Netherlands.
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Aengevaeren WRM, Laarman GJ, Suttorp MJ, Ten Berg JM, van Boven AJ, de Boer MJ, Piek JJ, van Ommen GVA, Bronzwaer JGF, Smits P, Deckers JW. Dutch guidelines for interventional cardiology: institutional and operator competence and requirements for training. Neth Heart J 2005; 13:416-422. [PMID: 25696433 PMCID: PMC2497356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023] Open
Abstract
Interventional cardiology is an expanding field within cardiovascular medicine and today it is generally accepted that cardiologists require specific training, knowledge and skills. Hospitals where coronary interventions are performed must be properly equipped and able to provide specialised care. Percutaneous coronary interventions are frequently used for coronary revascularisation. The public should have confidence in the uniformity of high quality care. Therefore, such quality of care should be maintained by certification of the individual operators, general guidelines for institutional requirements and formal audits. The Netherlands Society of Cardiology (NVVC) will be implementing a new registration system for cardiologists with a subspecialisation that will include registration for interventional cardiology. The NVVC asked the Working Group of Interventional Cardiology (WIC) to update the 1994 Dutch guidelines on operator and institutional competence, and requirements for training in interventional cardiology in order to incorporate them into the official directives. The present guidelines represent the expert opinion of the Dutch interventional cardiology community and are in accordance with international regulations. After two rounds of discussion, the NVVC approved the guidelines in November 2004 during the autumn meeting.
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van Tits LJH, Arioglu-Oral E, Sweep CGJ, Smits P, Stalenhoef AFH, Tack CJ. Anti-inflammatory effects of troglitazone in nondiabetic obese subjects independent of changes in insulin sensitivity. Neth J Med 2005; 63:250-5. [PMID: 16093575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
BACKGROUND Obesity is characterised by insulin resistance and by elevated levels of proinflammatory markers. We investigated whether, in the absence of changes in glucose, thiazolidinediones (TZDs) have anti-inflammatory effects and whether improvement of insulin sensitivity correlates with suppression of inflammatory markers. METHODS We performed a randomised double-blind placebo-controlled crossover study with troglitazone (400 mg daily for eight weeks) in 15 normoglycaemic obese subjects. We measured plasma high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), leptin, tissue-type plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1) and tumour necrosis factor-alpha (TNF-alpha) after each of the two treatment periods and in 13 age- and sex-matched lean individuals. RESULTS Obese subjects were insulin resistant (decreased glucose infusion rate (GIR) during euglycaemic hyperinsulinaemic clamp) and had higher plasma levels of hsCRP, IL-6, leptin, tPA, and PAI-1 compared with lean subjects. TNF-alpha also tended to be higher. Troglitazone improved insulin sensitivity (mean increase in whole body glucose uptake 23.1 +/- 10.5% (p = 0.047)) and normalised plasma concentrations of hsCRP, tPA and TNF-alpha, whereas it did not significantly change IL-6, leptin and PAI-1. Changes in GIR did not correlate with changes in inflammatory markers. CONCLUSION Troglitazone induces suppression of some of the inflammatory markers that are elevated in normoglycaemic obese subjects. The suppression of inflammatory markers, however, does not correlate with improvement in insulin sensitivity, suggesting involvement of partially differential mechanisms in these effects of TZDs.
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Affiliation(s)
- L J H van Tits
- Department of General Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands.
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Postma CT, Maessen SMJ, Thien T, Smits P. The effect of arginine vasopressin on endothelin production in the human forearm vascular bed. Neth J Med 2005; 63:199-204. [PMID: 16011011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
OBJECTIVES To study whether arginine vasopressin (AVP) can stimulate endothelin production and/or release in vivo, in the human forearm vasculature. DESIGN The effect of the infusion of AVP into the brachial artery on endothelin production across the human forearm vascular bed was studied in healthy male volunteers, and was compared with intra-arterial infusion of placebo. In another group the effects of AVP on endothelin production were studied after a prior infusion of L-NG-monomethyl-arginine (L-NMMA), a nitric oxide-synthase inhibitor. In a fourth group the effect of L-NMMA alone, without AVP infusion, on endothelin production was studied. METHODS We measured the effects of AVP, placebo, L-NMMA followed by AVP and L-NMMA followed by placebo on arterial and venous endothelin concentrations in the forearm of four groups, each consisting of five healthy male volunteers. Forearm blood flow was measured by strain gauge plethysmography. The endothelin production was calculated as forearm blood flow times (venous - arterial) endothelin concentration. RESULTS The group infused with L-NMMA followed by infusion of 8 ng AVP/min per dl forearm volume showed a significant rise in endothelin production from 1.3 (1.8) to 5.0 (2.0) pg/min/dl at 15 minutes (p<0.05, ANOVA). This rise in endothelin production was also significantly different from the endothelin production at 15 minutes in the other three groups (p<0.01, ANOVA). CONCLUSION In healthy male volunteers intra-arterial infusion of AVP induced a rise in endothelin production in the forearm within 15 minutes, but only after prior infusion of L-NMMA. This observation suggests that the AVP-induced production of nitric oxide offsets AVP-mediated release of endothelin.
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Affiliation(s)
- C T Postma
- Department of Internal Medicine, Division of General Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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Vervoort G, Veldman B, Berden JHM, Smits P, Wetzels JFM. Glomerular hyperfiltration in type 1 diabetes mellitus results from primary changes in proximal tubular sodium handling without changes in volume expansion. Eur J Clin Invest 2005; 35:330-6. [PMID: 15860045 DOI: 10.1111/j.1365-2362.2005.01497.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Glomerular hyperfiltration plays a role in the pathophysiology of diabetic nephropathy. An increase in the glomerular filtration rate (GFR) could result from primary actions at the glomerular/vascular level or could be the consequence of a primary increase in proximal tubular sodium reabsorption resulting in systemic volume expansion. Recently it was hypothesized that an increase in sodium reabsorption may lead to glomerular hyperfiltration through the tubulo-glomerular feedback mechanism (tubular-hypothesis) without volume expansion. DESIGN We have studied 54 normoalbuminuric patients with type 1 diabetes. The GFR was measured by inulin clearance. Proximal and distal sodium reabsorption were calculated according to standard formulas using the free water clearance technique. Plasma volume, measured by the (125)I-albumin method, atrial natriuretic peptide (ANP) and the second messenger cyclic guanosine-3,5-monophosphate (c-GMP) were used as markers of extracellular volume expansion. RESULTS Glomerular hyperfiltration (GFR >or= 130 mL min(-1) 1.73 m(-2)) was present in 14 out of 55 patients with diabetes (25%). There were no differences in plasma volume between normo-(NF) and hyper-filtrating (HF) patients (2933 +/- 423 in NF vs. 3026 +/- 562 mL in HF, NS). Also plasma ANP and c-GMP levels were not significantly different between the groups. The fractional proximal reabsorption of sodium was significantly increased in HF [fPRNa(+) (%) 90.1 +/- 2.0 vs. 91.5 +/- 1.6, P = 0.02]. There were no differences in distal sodium reabsorption or distal sodium load (approximately macula densa concentration of NaCl) in both groups. CONCLUSIONS Our data suggest that the primary event in diabetic glomerular hyperfiltration is an increase in proximal tubular sodium reabsorption. They do not support the hypothesis that systemic volume expansion or ANP mediate glomerular hyperfiltration in patients with normoalbuminuric type 1 diabetes. As such, changes in tubular sodium handling most probably influence tubulo-glomerular feedback.
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Affiliation(s)
- G Vervoort
- Department of General Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands.
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Abstract
RATIONALE L-NMMA is widely used in venous occlusion plethysmography studies to determine baseline NO production. Studies using L-NMMA indicate that endothelial dysfunction is present early in the course of diabetic microvascular complications. However, the optimal dose to maximally inhibit NO-production is unknown. OBJECTIVE To determine the L-NMMA-dose that maximally reduces basal forearm blood flow (FBF). To investigate whether there are any differences in the response to L-NMMA between non-complicated type 1 diabetes patients and control subjects. METHODS In eight non-complicated type 1 diabetes patients and nine healthy subjects FBF-responses to intra-arterial infusion of increasing doses of L-NMMA (0.01-1.6 mg/min/dL forearm volume [FAV]) were measured using the perfused forearm technique. RESULTS Infusion of 0.8 mg/min/dL maximally reduced FBF. The dose of 1.6 mg/min/dL did not additionally reduce FBF. No differences existed between non-complicated type 1 diabetes patients and controls with regard to EC50 (0.017 +/- 0.02 resp. 0.22 +/- 0.02 mg L-NMMA/min/dL) or maximal vasoconstrictive response (Delta FBF: 1.13 +/- 0.4 resp. 0.97 +/- 0.4 mL/min/dL). Throughout the study blood pressure increased significantly in both groups, possibly reflecting a systemic vasoconstrictive effect of L-NMMA. CONCLUSIONS The maximal vasoconstrictive dose was 0.8 mg/min/dL in type 1 diabetes patients as well as the control subjects. There were no significant differences between non-complicated type 1 diabetes subjects and controls with regard to the pharmacodynamics of L-NMMA. At high dosages of L-NMMA a systemic effect can not be ruled out.
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Affiliation(s)
- B A J Veldman
- Department of Internal Medicine, University Medical Center St. Radboud, Nijmegen, The Netherlands
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Bisseling TM, Wouterse AC, Steegers EAP, Elving L, Russel FGM, Smits P. Dysfunction of the cyclo-oxygenase pathway in the foetoplacental circulation in Type 1 diabetes mellitus. Diabet Med 2005; 22:503-6. [PMID: 15787680 DOI: 10.1111/j.1464-5491.2005.01437.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM In diabetes, perinatal morbidity is significantly increased. This may partly be related to functional changes in the foetoplacental vascular bed. In diabetes models, a defect in the cyclo-oxygenase pathway is a common observation. Therefore, we hypothesized that the human foetoplacental circulation of diabetic patients is characterized by dysfunction of the cyclo-oxygenase pathway, as well. METHODS We performed ex-vivo perfusions of isolated placental cotyledons from healthy women (n = 14) and from patients with Type 1 diabetes (n = 9). The contribution of cyclo-oxygenase products to foetoplacental vascular tone was quantified by measuring the response to the cyclo-oxygenase inhibitor indomethacin. RESULTS Baseline foetoplacental arterial pressure was comparable between controls and diabetic women (mean +/- sem, 21.7 +/- 1.2 vs. 24.4 +/- 2.0 mmHg). Maximum foetoplacental arterial pressure at highest dose of indomethacin was 32.8 +/- 3.0 mmHg in controls vs. 27.3 +/- 2.3 mmHg in diabetic women. The indomethacin-induced increase in pressure was reduced in diabetes (2.9 +/- 0.7 vs. 11.2 +/- 2.4 mmHg in controls, P = 0.01). CONCLUSIONS Under baseline conditions, the net effect of all cyclo-oxygenase products in the foetoplacental vascular bed is vasodilation. In diabetes, this vasodilator effect seems significantly impaired.
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Affiliation(s)
- T M Bisseling
- Department of Pharmacology-Toxicology, University Medical Cenger, Nijmegen, the Netherlands
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Abstract
INTRODUCTION Elevated plasma levels of total homocysteine are related to the development of vascular complications. Patients with diabetes mellitus are particularly at risk for the development of these complications. Several factors determine plasma total homocysteine including renal function. AIMS As early Type 1 diabetes is characterized by a relative glomerular hyperfiltration, increased renal clearance could contribute to decreased levels of homocysteine as observed in Type 1 diabetes mellitus. Therefore we investigated the relationship between plasma total homocysteine and the glomerular filtration rate (GFR). METHODS In 92 Type 1 diabetes patients and 44 control subjects, we measured GFR and effective renal plasma flow (ERPF) by means of continuous infusion of inulin and p-aminohippurate. Fasting plasma total homocysteine was measured using high performance liquid chromatography. RESULTS GFR (121 +/- 21 resp. 104 +/- 14 ml/min; P < 0.001) and ERPF (563 +/- 127 resp. 516 +/- 121 ml/min; P = 0.05) were significantly higher in Type 1 diabetes patients as compared with control subjects. Plasma total homocysteine was reduced in Type 1 diabetes patients as compared with control subjects (11.0 +/- 4.5 resp. 13.4 +/- 7 micromol/l; P = 0.01). Plasma total homocysteine was strongly correlated with GFR (Type 1 diabetes patients: r = -0.43, P < 0.001; control subjects: r = -0.39, P = 0.01). CONCLUSION GFR is a major determinant of plasma total homocysteine levels in Type 1 diabetes patients as well as control subjects. The reduced plasma total homocysteine levels in diabetes patients can be explained by an increased GFR.
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Affiliation(s)
- B A J Veldman
- Department of Internal Medicine, University Medical Center, Nijmegen, Nijmegen, The Netherlands
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