Simon Malenfant

Publications (5) View all

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  Available from: Simon Malenfant

  Article: The Emergence of New Therapeutic Targets in Pulmonary Arterial Hypertension: from Now to Near Future

  Simon Malenfant, Guillaume Margaillan, Jérémie-Edwin Loehr, Sébastien Bonnet, Steeve Provencher
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  ABSTRACT: Pulmonary arterial hypertension (PAH) is a vascular remodeling disease that pathologically increases pulmonary vascular resistance. Ultimately, this leads to right ventricular failure and premature death. Current therapeutic strategies are mainly designed to induce relaxation of the pulmonary arteries, but are not directly aimed to improve vascular remodeling that characterize PAH. While these treatments modestly improve patient symptoms, pulmonary hemodynamics and survival, none of them are curative and approximately 15% of patients die within one year of medical follow-up despite treatment. Within the last five years, tremendous advances in our understanding of the PAH pathophysiology have arisen. These advances have a high potential for the development of better patient care by providing novel therapeutic targets. The goal of this report is to review the current PAH treatments, as well as novel therapies that will pave the future in this devastating disease.
  Expert Review of Respiratory Medicine 02/2013; 7(1):43-55.
• Article: Signal transduction in the developpement of pulmonary aterial hypertension

  Simon Malenfant, Anne-Sophie Neyron, François Potus, Roxanne Paulin, Jolyane Meloche, Steeve Provencher, Sébastien Bonnet
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  ABSTRACT: Pulmonary arterial hypertension (PAH) is a unique disease. It is not a disease of the lung properly speaking. It can be more seen as a microvascular disease occurring mainly in the lungs and affecting the heart. At the cellular level, PAH is characterized by inflammation, vascular tone imbalance, proliferation of pulmonary arterial smooth muscle cell and reduction of their apoptosis level. At a clinical level, the aforementioned abnormal vascular properties alter physically the pulmonary circulation and ventilation, which greatly influence the right ventricle function as it highly correlates with the disease severity. Consequently, right heart failure remains the principal cause of death within this cohort of patients. While current treatment modestly improve patient’s condition, none of them are curative and, as of today, new therapies are lacking. However, the future holds potential new therapies that might have positive influence on the quality of life of the patient. This article will first review the different molecular pathway implicated in the pathobiology of PAH and their influence on the clinical presentation of the disease. The second part will review tomorrow’s future putative therapies for PAH.
  Pulmonary Circulation. 01/2013;
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  Article: Repeatability and responsiveness of exercise tests in pulmonary arterial hypertension.

  Vincent Mainguy, Simon Malenfant, Anne-Sophie Neyron, Sébastien Bonnet, François Maltais, Didier Saey, Steeve Provencher
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  ABSTRACT: Exercise tolerance in pulmonary arterial hypertension (PAH) is most commonly assessed by the 6-min walk test (6MWT). Whether endurance exercise tests are more responsive than the 6MWT remain unknown.Twenty stable PAH patients (mean age: 53[15]; mean pulmonary arterial pressure: 44[16]) already on PAH monotherapy completed the 6MWT, the endurance shuttle walk test (ESWT) and the cycle endurance test (CET) before and after the addition of sildenafil citrate 20 mg tid or placebo for 28 days in a randomized double-blind crossover setting. Pre/post-placebo tests were used to assess repeatability of each exercise test, whereas pre/post-sildenafil citrate tests were used to assess their responsiveness.Sildenafil citrate led to placebo-corrected changes in exercise capacity of +18(25)meters (p=0.02), +58(235)seconds (p=0.58), and +29(77)seconds (p=0.09), for the 6MWT, the ESWT and the CET, respectively. The 6MWT was associated a lower coefficient of variation between repeated measures (3 vs. 18 vs. 13%), resulting in a higher standardized response mean compared to endurance tests (0.72, 0.25 and 0.38 for the 6MWT, the ESWT and CET, respectively).The 6MWT had the best ability to capture changes in exercise capacity when sildenafil citrate was combined to patients' baseline monotherapy, supporting its use as an outcome measure in PAH.
  European Respiratory Journal 10/2012; · 5.89 Impact Factor
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  Article: The incidence of behaviours associated with body checking among youth ice hockey players

  Simon Malenfant, Claude Goulet, Luc Nadeau, Denis Hamel, Carolyn A Emery
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  ABSTRACT: Objectives: To determine if a difference exists between the incidence and intensity of the physical contacts of Pee Wee (aged 11–12 years) ice hockey players according to whether the players participate in a league in which body checking is permitted (Calgary, Canada) compared to a league in which body checking is not permitted (Québec City, Canada). 9 10 11 12 Design: Cohort study conducted in Québec City and Calgary during the 2007–2008 Pee Wee ice hockey season. Methods: Ten games were randomly selected for each city (n = 20) and analysed. Games were videotaped and subsequently analysed with a validated observation system allowing quantification of the intensity of the various physical contacts. Incidence rate ratios (RR) based on multivariate Poisson regression were used to compare the physical contacts between provinces. All analyses were controlling for game period, score difference, and zone on the playing surface. 13 14 15 16 Results: A total of 2418 physical contacts with the trunk and 757 other physical contacts were observed. Very light intensity trunk physical contacts were more frequent in Québec City (adjusted incidence RR [ARR]: 0.68; 95% CI: 0.48–0.97). Very high intensity trunk physical contacts were more frequent in Calgary (ARR: 12.72; 95% CI: 4.48–36.14). Hooking (ARR: 0.89; 95% CI: 0.84–0.95) and slashing (ARR: 0.91; 95% CI: 0.85–0.97) were more frequent in Québec City. 17 18 19 20 Conclusion: Results suggest that players’ behaviours are different in leagues where body checking is permitted compared to leagues where it is not permitted. Policy allowing body checking in Pee Wee ice hockey increases the frequency and intensity of physical contacts.
  Journal of Science and Medicine in Sport. 01/2012; 15(1):463-467.
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  Article: Assessment of daily life physical activities in pulmonary arterial hypertension.

  Vincent Mainguy, Steeve Provencher, François Maltais, Simon Malenfant, Didier Saey
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  ABSTRACT: In pulmonary arterial hypertension (PAH), the six-minute walk test (6MWT) is believed to be representative of patient's daily life physical activities (DL(PA)). Whether DL(PA) are decreased in PAH and whether the 6MWT is representative of patient's DL(PA) remain unknown. 15 patients with idiopathic PAH (IPAH) and 10 patients with PAH associated with limited systemic sclerosis (PAH-SSc) were matched with 15 healthy control subjects and 10 patients with limited systemic sclerosis without PAH. Each subject completed a 6MWT. The mean number of daily steps and the mean energy expenditure and duration of physical activities >3 METs were assessed with a physical activity monitor for seven consecutive days and used as markers of DL(PA). The mean number of daily steps and the mean daily energy expenditure and duration of physical activities >3 METs were all reduced in PAH patients compared to their controls (all p<0.05). The mean number of daily steps correlated with the 6MWT distance for both IPAH and PAH-SSc patients (r = 0.76, p<0.01 and r = 0.85, p<0.01), respectively. DL(PA) are decreased in PAH and correlate with the 6MWT distance. Functional exercise capacity may thus be a useful surrogate of DL(PA) in PAH.
  PLoS ONE 01/2011; 6(11):e27993. · 4.09 Impact Factor