Philippe Connes

Publications (101) View all

• Source

  Available from: Xavier Waltz

  Article: Hemorheological risk factors of acute chest syndrome and painful vaso-occlusive crisis in children with sickle cell disease.

  Yann Lamarre, Marc Romana, Xavier Waltz, Marie-Laure Lalanne-Mistrih, Benoit Tressieres, Lydia Divialle-Doumdo, Marie-Dominique Hardy-Dessources, Jens Vent-Schmidt, Marie Petras, Cedric Broquere, Frederic Maillard, Vanessa Tarer, Maryse Etienne-Julan, Philippe Connes
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  ABSTRACT: Background. Little is known about the effects of blood rheology on the occurrence of acute chest syndrome and painful vaso-occlusive crises in children with sickle cell anemia and hemoglobin SC disease. Design and methods. To address this issue, steady-state hemorheological profiles (blood viscosity, red blood cell deformability, aggregation properties) and hematological parameters were assessed in 44 children with sickle cell anemia and 49 children with hemoglobin SC disease (8-16 years old), followed since birth. Charts were retrospectively reviewed to determine prior acute chest syndrome or vaso-occlusive episodes, and rates of these complications were calculated. Results. Multivariate analysis revealed that: 1) a higher steady-state blood viscosity was associated with a greater rate of vaso-occlusive crises in children with sickle cell anemia, but not in children with hemoglobin SC disease; 2) a higher steady-state red blood cell disaggregation threshold was associated with previous history of acute chest syndrome in children with hemoglobin SC disease and boys with sickle cell anemia. Conclusions. Our results indicate for the first time that the red blood cell aggregation properties may play a role in the pathophysiology of acute chest syndrome in children with hemoglobin SC disease and boys with sickle cell anemia. In addition, whereas greater blood viscosity is associated with greater rate of vaso-occlusive crises in children with sickle cell anemia, no association was found in children with hemoglobin SC disease, underscoring differences in the etiology of vaso-occlusive crises between sickle cell anemia and hemoglobin SC disease.
  Haematologica 06/2012; · 6.42 Impact Factor
• Article: Effects of hydration and water deprivation on blood viscosity during a soccer game in sickle cell trait carriers.

  Mor Diaw, Abdoulaye Samb, Saliou Diop, Niama Diop Sall, Abdoulaye Ba, Fallou Cissé, Philippe Connes
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  ABSTRACT: The present study compared the changes in blood viscosity, hydration status, body temperature and heart rate between a group of sickle cell trait (SCT) carriers and a control (Cont) group before and after a soccer game performed in two conditions: one with water offered ad libitum (hydration condition; Hyd) and the other one without water (dehydration condition; Dehyd). Blood viscosity and haematocrit per blood viscosity ratio (HVR; an index of red blood cell oxygen transport effectiveness) were measured before and at the end of each game. Resting blood viscosity was greater in the SCT carriers than in the Cont group. The increase of blood viscosity over baseline at the end of the game in the Cont group was similar in the two conditions. In contrast, the change in blood viscosity occurring in SCT carriers during soccer games was dependant on the experimental condition: (1) in Dehyd condition, blood viscosity rose over baseline; (2) in Hyd condition, blood viscosity decreased below resting level reaching Cont values. The Cont group had higher HVR than SCT carriers at rest. HVR remained unchanged in the Cont group at the end of the games, whatever the experimental condition. Although HVR of SCT carriers decreased below baseline at the end of the game performed in Dehyd condition, it increased over resting level in Hyd condition reaching the values of the Cont group. Our study demonstrated that ad libitum hydration in exercising SCT carriers normalises the blood hyperviscosity.
  British journal of sports medicine 06/2012; · 2.55 Impact Factor
• Source

  Available from: Aurélien Pichon

  Article: Relationship between Acute Chest Syndrome and the sympatho-vagal balance in adults with hemoglobin SS disease; a case control study.

  Jennifer M Knight-Madden, Philippe Connes, Andre Bowers, Danitza Nebor, Marie-Dominique Hardy-Dessources, Marc Romana, Harvey Reid, Aurélien P Pichon, Jean-Claude Barthélémy, Vanessa B Cumming, Jacques Elion, Marvin Reid
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  ABSTRACT: The present study evaluated the relationship between acute chest syndrome (ACS) and autonomic nervous system (ANS) activity in patients with hemoglobin SS disease (SCD). Nine patients had suffered ACS were matched by age and gender to patients who had not suffered ACS and ANS activity, pulmonary function and history of painful crisis were compared. Correlations between number of episodes of ACS suffered and these variables were determined. The results demonstrated that 1) patients with a history of ACS ever had lower parasympathetic nervous system (PNS) activity and lower global ANS activity than patients with no ACS ever (p < 0.05), 2) the number of ACS episodes ever negatively correlated (p < 0.05) with PNS activity and global ANS activity and 3) There were no significant associations between lung function or a history of painful crisis in these patients. In conclusion, a history of ACS was associated with ANS dysfunction in adults with SCD.
  Clinical hemorheology and microcirculation 03/2012; · 3.40 Impact Factor
• Article: Abnormal flow adhesion of sickle red blood cells to human placental trophoblast extracellular matrix.

  Yann Lamarre, Stéphane Petres, Marie-Dominique Hardy-Dessources, Stéphane Sinnapah, Marc Romana, Sandrine Laurance, Nathalie Lemonne, Jürg Gysin, Philippe Connes
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  ABSTRACT: Pregnancy in sickle cell disease (SCD) has been associated with increased complications such as vaso-occlusive crises, severe anemia and foetal loss. It has been proposed that the sickling of red blood cells (RBCs) inside the placenta circulation could participate to these complications. The present study investigated the adhesion of sickle RBCs on human trophoblast-derived cell and its extracellular matrix. Results demonstrated 1) similar adhesion of sickle RBCs and healthy RBCs to trophoblast but 2) a greater adhesion of sickle RBCs to the extracellular matrix of trophoblasts as compared with healthy RBCs. This greater adhesion could partly involve the Lu/BCAM glycoproteins and could participate to the complications reported in SCD pregnant women.
  Clinical hemorheology and microcirculation 01/2012; 51(3):229-34. · 3.40 Impact Factor
• Source

  Available from: Aurélien Pichon

  Article: Blood viscosity and hemodynamics during exercise.

  Philippe Connes, Aurélien Pichon, Marie-Dominique Hardy-Dessources, Xavier Waltz, Yann Lamarre, Michael J Simmonds, Julien Tripette
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  ABSTRACT: We tested the effects of submaximal exercise on blood viscosity (η(b)), nitric oxide production (NO) and hemodynamics. Relationships between the exercise-induced changes that occurred in these parameters were investigated. Nine subjects performed exercise for 15 min at 105% of the first ventilatory threshold. Mean arterial pressure (MAP) and cardiac output (Qc) were measured, allowing the determination of systemic vascular resistance (SVR). Blood was sampled at rest and at the end of exercise. The η(b) was determined at high shear rate and was used to calculate systemic vascular hindrance (VH). NO production was estimated by measuring plasma concentrations of NO stable end products (NOx). Qc, MAP, η(b) and NOx, increased with exercise, whereas SVR and VH decreased. The changes between rest and exercise were calculated and tested for correlations. We observed: 1) a positive correlation between the increase in η(b) and the increase in NOx; 2) a negative correlation between the increase in NOx and the decrease in VH; 3) a negative correlation between the increase in η(b) and the decrease in SVR. Although the increase in Qc and blood flow during exercise probably promoted NO production due to shear dependent stimulation of the endothelium, the present results also support that the rise in η(b) during exercise may be necessary for NO production and adequate vasodilation.
  Clinical hemorheology and microcirculation 01/2012; 51(2):101-9. · 3.40 Impact Factor