This article summarizes Françoise Dieterlen\'s major scientific discoveries about the hematopoietic and endothelial systems during her 40 years\' career. Her most remarkable achievements include notably the demonstration of an intraembryonic source of hematopoietic stem cells, the characterization of the polarization of the aorta, the identification of a hemogenic endothelium as well as that of the allantois as an organ of hematopoietic amplification in the mouse embryo, and the demonstration of the existence of a hemogenic endothelium capable of generating hematopoietic stem cells in the bone marrow of the chicken and mouse embryo. While this last discovery was not made directly by Françoise Dieterlen, it was inspired by the many conversations I have had with her and the lessons she has taught me throughout my career. Her rich career will forever shape the field of hematopoietic development, in which she will remain a guiding figure.
UNASSIGNED: Plongée avec Françoise Dieterlen dans l’origine des cellules souches hématopoïétiques.
UNASSIGNED: Cet article récapitule les principales découvertes scientifiques réalisées par Françoise Dieterlen sur le système hématopoïétique et endothélial au cours de sa carrière qui s’est déroulée sur plus de 40  années. Ses contributions, toutes majeures, portent notamment sur la démonstration d’une source intra-embryonnaire de cellules souches hématopoïetiques impliquant la polarisation de l’aorte et la formation d’un endothélium homogénique, la mise en évidence de l’allantoïde comme organe d’amplification hématopoïétique chez l’embryon de souris et la démonstration de l’existence d’un endothélium hémogénique capable de générer des cellules souches hématopoïétiques dans la moelle osseuse de l’embryon de poulet et de souris. Cette dernière découverte, bien que n’ayant pas été réalisée directement par Françoise Dieterlen, a été inspirée par les nombreuses discussions que j’ai pu avoir avec elle et les enseignements qu’elle m’a prodigués au début de ma carrière. Les avancées remarquables accomplies par Françoise Dieterlen dans le champ du développement hématopoïétique sont unanimement reconnues par tous les spécialistes pour qui elle reste à jamais l’une des fondatrices de ce domaine de recherche.

Acitretin is a member of vitamin A-derived retinoids, and its effect on vascular smooth muscle had not yet been studied. The aim of this study is to investigate the effect of acitretin, a retinoid, on vascular smooth muscle contractility. Thoracic aorta preparations obtained from 34 male Sprague-Dawley rats (355 ± 15 g) were studied in isolated organ baths containing Krebs-Henseleit solution. The relaxation responses were obtained with acitretin (10-12-10-4 M) in endothelium-preserved and endothelium-denuded aorta preparations precontracted with submaximal concentration of phenylephrine (10-6 M). The role of retinoic acid receptors (RARs), nitric oxide, adenylyl, and guanylyl cyclase enzymes, and potassium channels in these relaxation responses were investigated. Acitretin produced concentration-dependent relaxations, which were independent of its solvent dimethylsulfoxide (DMSO), in endothelium-denuded phenylephrine-precontracted thoracic aorta preparations. While incubation with the RAR antagonist (AGN193109, 10-5 M) had no effect on these relaxations; nitric oxide synthase inhibitor (L-NG-Nitro arginine methyl ester (L-NAME), 10-4 M), adenylyl cyclase inhibitor (SQ2253, 10-5 M), guanylyl cyclase inhibitor (oxadiazolo [4,3-a] quinoxalin-1-one (ODQ), 10-6 M), and potassium channel blocker (tetraethylammonium (TEA), 10-2 M) significantly eliminated the relaxation responses induced by acitretin. Acitretin induces relaxation in rat isolated thoracic aorta preparations without endothelium, which may be mediated by nitric oxide, cyclic adenosine monophosphate, and cyclic guanosine monophosphate-dependent kinases and potassium channels.

Insulin resistance is a feature of pregnancy and is associated with increased levels of angiotensin II (Ang II) and insulin. Therefore, pregnancy may change insulin-induced vasodilation through changes in Ang II receptors. Insulin-induced vasorelaxation was evaluated in phenylephrine-precontracted aortic rings of pregnant and non-pregnant rats, using a conventional isolated organ preparation. Experiments were performed in thoracic or abdominal aorta rings with or without endothelium in the presence and absence of NG-nitro-L-arginine methyl ester (L-NAME) (10-5 M), losartan (10-7 M), or PD123319 (10-7 M). AT1 and AT2 receptor expressions were detected by immunohistochemistry. Insulin-induced vasodilation was endothelium- and nitric oxide-dependent and decreased in the thoracic aorta but increased in the abdominal segment of pregnant rats. The insulin\'s vasorelaxant effect was increased by losartan mainly on the thoracic aorta. PD123319 decreased insulin-induced vasorelaxation mainly in the pregnant rat abdominal aorta. AT1 receptor expression was decreased while AT2 receptor expression was increased by pregnancy. In conclusion, pregnancy changes insulin-induced vasorelaxation. Moreover, insulin vasodilation is tonically inhibited by AT1 receptors, while AT2 receptors appear to have an insulin-sensitizing effect. The role of pregnancy and Ang II receptors differ depending on the aorta segment. These results shed light on the role of pregnancy and Ang II receptors on the regulation of insulin-mediated vasodilation.

Oleuropein (OLE) is the main bioactive ingredient in the leaves of the olive plant Olea europaea L. (Oleaceae), which has proven beneficial due to the antiinflammatory, antiatherogenic, anticancer, antimicrobial, and antiviral effects. This study aimed to investigate the antihypertensive and vasodilator potential of OLE by analyzing its acute effects on spontaneous atrial contractions and vasomotor responses of the isolated thoracic aorta in rats. We showed that the application of OLE induces negative chronotropic and inotropic effects on the heart. OLE also causes mild aortic vasodilation given that the maximal reduction in tension of intact aortic rings precontracted with phenylephrine was approximately 30%. This vasodilation is likely dependent on the nitric oxide released from the endothelium based on the effect obtained on denuded and phenylephrine precontracted aortic rings and responses reordered following vasoconstriction induced by high concentrations of K+ and heparin. Our findings provide a basis for further testing of OLE cardiovascular effects, which may lead to subsequent clinical research for its application in the treatment of hypertension and heart disease.

The floating mural thrombus of abdominal aorta is a rare and serious pathology detected as cause of peripheral and visceral embolism. Isolated aortic mural thrombosis is an unusual pathology occurring in an apparently normal aorta. A thorough search of embolic source must be initiated. Therapeutic management is based on systemic anticoagulation with the use of surgical approach in some cases.

Cyclosporine, an immunosuppressive drug, exhibits a toxic effect on renal and vascular systems. The present study investigated whether resveratrol treatment alleviates renal and vascular injury induced by cyclosporine. Cyclosporine (25 mg/kg per day, s.c.) was given for 7 days to rats either alone or in combination with resveratrol (10 mg/kg per day, i.p.). Relaxation and contraction responses of aorta were examined. Serum levels of blood urea nitrogen, creatinine, angiotensin II, and angiotensin 1-7 were measured. Histopathological examinations as well as immunostaining for 4-hydroxynonenal and nitrotyrosine were performed in the kidney. RNA expressions of renin-angiotensin system components were also measured in renal and aortic tissues. Cyclosporine decreased the endothelium-dependent relaxation and increased vascular contraction in the aorta. It caused renal tubular degeneration and increased immunostaining for 4-hydroxynonenal, an oxidative stress marker. Cyclosporine also caused upregulations of the vasoconstrictive renin-angiotensin system components in renal (angiotensin-converting enzyme) and aortic (angiotensin II type 1 receptor) tissues. Resveratrol co-treatment prevented the cyclosporine-related deteriorations. Moreover, it induced the expressions of vasodilatory effective angiotensin-converting enzyme 2 and angiotensin II type 2 receptor in aorta and kidney, respectively. We conclude that resveratrol may be effective in preventing cyclosporine-induced renal tubular degeneration and vascular dysfunction at least in part by modulating the renin-angiotensin system.

Various protein-based supplements are at least periodically consumed by 30%-40% of sportspeople. The current study compares cardiovascular effects of diet supplementation with 2 different protein-rich products: bee pollen and whey protein. Thirty Wistar rats were divided into 2 groups, one subjected to daily moderate physical activity and one not. Each group consisted of 3 subgroups: control, whey-protein-supplemented, and bee-pollen-supplemented. After 8 weeks, rats were decapitated, and proximal parts of thoracic aortas were collected and embedded in paraffin blocks. Histological slides were stained according to standard hematoxylin and eosin, Masson\'s trichrome, and Verhoeff - Van Gieson staining. Special immunohistochemical stains against neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS), and alpha smooth muscle actin were also prepared. Histological evaluation revealed noticeable changes in all supplemented groups: disturbances in elastic laminae, slight increase in collagen deposition, and significantly lowered nNOS and eNOS expression. The prevalence of small atherosclerotic plaques was the highest in non-running supplemented groups, while in running supplemented groups it resembled the prevalence in control groups. Both running groups had thinner tunica media than control. Both supplements exert visible effects on aortic structure, but the difference between them is far less evident. In some aspects, however, the bee pollen seems to be even slightly more harmful, which may be related to various possible contaminants like mycotoxins or pesticides.

OBJECTIVE: To study the prevalence of atherosclerosis (aortic and coronary lesions) in Senegalese people, to determine main risks factors and morphological patterns.
METHODS: A prospective autopsy study was conducted in the pathology department of Aristide Le Dantec Hospital (Dakar-Senegal) where 116 specimens aged over 5 years old were studied.
RESULTS: Autopsy study of 116 Senegalese specimens for atherosclerotic lesions revealed aortic lesions in 100 cases (86%), aortic and coronary lesions both in 48 cases. There were 88 men versus 12 women. The median age was 37.1 years comprised 5 to 77 years old. Hypertensive, smoking and abdominal obesity were detected respectively in 5 cases, 37 cases and 33 cases. In aortic vessel, the main lesions detected were severe fibrous plaques detected in 40 cases. In coronary arteries, fibrous plaques were detected in 18 cases, severe fibrous plaques in 17 cases.
CONCLUSIONS: Our study in Senegalese population showed existence of atherosclerotic lesions. These lesions were more responsible for complications as myocardial infarction.

OBJECTIVE: Studies of the influence of aortic root remodelling on the left ventricle are scarce in sub Saharan Africa even though this region has got high prevalence of arterial hypertension which is positively related to sinuses of Valsalva diameter. The present work aims to determine the frequency of the proximal aortic root enlargement and to evaluate its association with the left ventricle structure and function respectively among Congolese patients.
METHODS: Four hundreds and three (403) patients who realised transthoracic cardiac echography were recruited. The association between the proximal aortic root diameter and the left ventricular echocardiographic parameters was modelised in a multiple linear regression using the Stepwise method.
RESULTS: Among the 403 patients, 69.4% were hypertensive. A multivariate linear regression analysis showed correlations between the proximal aortic root diameter and the left ventricular mass (β=1.12; P=0.01), the left ventricular diastolic diameter (β=0.26, P=0.001) and the E/A ratio (β=-0.02; P<0.0001) respectively. The independent predictor of the proximal aortic root diameter were age (β=0.06, P=0.0006), duration of arterial hypertension (β=0.11, P=0.002) and diastolic blood pressure (β=0.03; P=0.02). The frequency of the proximal aortic root dilatation was 3.5%.
CONCLUSIONS: These results infancies the importance of including the proximal aortic root dilatation as specific infra clinic risk factor among Congolese.

Arterial thrombosis of the newborn is rare and associated with poor prognosis, often attributed to umbilical arterial catheterization. The aortic and spontaneous forms are exceptional. Its severity requires fast and effective treatment. Although therapeutic means are numerous, no consensus has been established to date although thrombolysis and heparin therapy appear to give good results depending on the site and extent of thrombosis. We report a case of extensive thrombosis of the abdominal aorta in a 5-day-old newborn, revealed by acute hypernatremic dehydration. Thrombosis was not related to umbilical catheterization. The diagnosis was confirmed by Doppler ultrasound with discovery during the etiologic assessment of an authentic protein S deficiency. This observation was the occasion for a review of the literature concerning the evolutionary and therapeutic clinical aspects of neonatal arterial thrombosis.