Characterization of spontaneous bone marrow recovery after sublethal total body irradiation: importance of the osteoblastic/adipocytic balance.

in PLoS ONE (2012), 7(2), 30818

Many studies have already examined the hematopoietic recovery after irradiation but paid with very little attention to the bone marrow microenvironment. Nonetheless previous studies in a murine model of ... [more ▼]

Many studies have already examined the hematopoietic recovery after irradiation but paid with very little attention to the bone marrow microenvironment. Nonetheless previous studies in a murine model of reversible radio-induced bone marrow aplasia have shown a significant increase in alkaline phosphatase activity (ALP) prior to hematopoietic regeneration. This increase in ALP activity was not due to cell proliferation but could be attributed to modifications of the properties of mesenchymal stem cells (MSC). We thus undertook a study to assess the kinetics of the evolution of MSC correlated to their hematopoietic supportive capacities in mice treated with sub lethal total body irradiation. In our study, colony-forming units - fibroblasts (CFU-Fs) assay showed a significant MSC rate increase in irradiated bone marrows. CFU-Fs colonies still possessed differentiation capacities of MSC but colonies from mice sacrificed 3 days after irradiation displayed high rates of ALP activity and a transient increase in osteoblastic markers expression while ppargamma and neuropilin-1 decreased. Hematopoietic supportive capacities of CFU-Fs were also modified: as compared to controls, irradiated CFU-Fs significantly increased the proliferation rate of hematopoietic precursors and accelerated the differentiation toward the granulocytic lineage. Our data provide the first evidence of the key role exerted by the balance between osteoblasts and adipocytes in spontaneous bone marrow regeneration. First, (pre)osteoblast differentiation from MSC stimulated hematopoietic precursor's proliferation and granulopoietic regeneration. Then, in a second time (pre)osteoblasts progressively disappeared in favour of adipocytic cells which down regulated the proliferation and granulocytic differentiation and then contributed to a return to pre-irradiation conditions. [less ▲]

Etude génétique et anatomopathologique du syndrome de McCune-Albright chez l'adulte

in Annales d'Endocrinologie (2010, September), 71(5), 345

Etude génétique et anatomopathologique du syndrome de McCune-Albright chez l'adulte

in 27ème Congrès de la Société Française d'Endocrinologie - Deauville, 29 septembre - 2 octobre 2010 (2010, September)

Angiosarcome sur lymphoedeme chronique: un cas de syndrome de Stewart-Treves.

in Revue Médicale de Liège (2009), 64(7-8), 409-13

The Stewart-Treves Syndrome is defined as an angiosarcoma (very aggressive malignant tumor originating from endothelial cells) appearing in a specific clinical setting. This tumor develops in patients ... [more ▼]

The Stewart-Treves Syndrome is defined as an angiosarcoma (very aggressive malignant tumor originating from endothelial cells) appearing in a specific clinical setting. This tumor develops in patients suffering from chronic lymphedema of the upper limb following mastectomy and axillary lymph node dissection for breast cancer. The diagnosis relies on medical history, clinical examination and a histological assesment (biopsy or resection). This syndrome represents a rare clinical entity. Unfortunately, the prognosis is poor. A large surgical resection is the treatment of choice if the patient is a candidate for a surgical resection with a curative intent Radiotherapy is sometimes used as a palliative local treatment. Chemotherapy is only used in more advanced cases, not curable by surgery alone. [less ▲]

Human bone marrow adipocytes block granulopoiesis through neuropilin-1-induced granulocyte colony-stimulating factor inhibition.

in Stem Cells (2008), 26(6), 1556-64

Adipocytes are part of hematopoietic microenvironment, even though up to now in humans, their role in hematopoiesis is still questioned. We have previously shown that accumulation of fat cells in femoral ... [more ▼]

Adipocytes are part of hematopoietic microenvironment, even though up to now in humans, their role in hematopoiesis is still questioned. We have previously shown that accumulation of fat cells in femoral bone marrow (BM) coincides with increased expression of neuropilin-1 (NP-1), while it is weakly expressed in hematopoietic iliac crest BM. Starting from this observation, we postulated that adipocytes might exert a negative effect on hematopoiesis mediated through NP-1. To test this hypothesis, we set up BM adipocytes differentiated into fibroblast-like fat cells (FLFC), which share the major characteristics of primitive unilocular fat cells, as an experimental model. As expected, FLFCs constitutively produced macrophage colony stimulating factor and induced CD34(+) differentiation into macrophages independently of cell-to-cell contact. By contrast, granulopoiesis was hampered by cell-to-cell contact but could be restored in transwell culture conditions, together with granulocyte colony stimulating factor production. Both functions were also recovered when FLFCs cultured in contact with CD34(+) cells were treated with an antibody neutralizing NP-1, which proved its critical implication in contact inhibition. An inflammatory cytokine such as interleukin-1 beta or dexamethasone modulates FLFC properties to restore granulopoiesis. Our data provide the first evidence that primary adipocytes exert regulatory functions during hematopoiesis that might be implicated in some pathological processes. Disclosure of potential conflicts of interest is found at the end of this article. [less ▲]

Syndrome de McCune-Albright : de la clinique à la pathologie

Scientific conference (2006, December 02)

Primary sarcoma of an abdominal aortic aneurysm

in Abdominal Imaging (2006), 31(1, Jan-Feb), 117-119

Primary tumors of the aorta are extremely rare and the diagnosis is made most often after surgery or autopsy. Because clinical symptoms of abdominal sarcoma are similar to those of occlusive or aneurysmal ... [more ▼]

Primary tumors of the aorta are extremely rare and the diagnosis is made most often after surgery or autopsy. Because clinical symptoms of abdominal sarcoma are similar to those of occlusive or aneurysmal disease, aortic sarcomas are frequently mistaken for these lesions. The imaging findings are frequently nonspecific and therefore do not allow a definitive preoperative diagnosis. We report a case of an epithelioid angiosarcoma in the vessel wall of an abdominal aortic aneurysm. [less ▲]

Comment j'explore... Une valeur élevée de calcitonine?

in Revue Médicale de Liège (2006), 61(3), 195-200

This article describes a case of lung cancer with associated hypercalcitoninemia in a man with a goitre. The case raises the problem of the differential diagnosis between medullary thyroid carcinoma and a ... [more ▼]

This article describes a case of lung cancer with associated hypercalcitoninemia in a man with a goitre. The case raises the problem of the differential diagnosis between medullary thyroid carcinoma and a neuroendocrine neoplasm with ectopic calcitonin secretion. The article first reviews the physiology of calcitonin, then outlines the diagnostic tests that are required to investigate hypercalcitoninemia and finally discusses the interpretation of test results. [less ▲]

L'echinococcose alveolaire: une zoonose d'apparition recente en Wallonie

in Revue Médicale de Liège (2005), 60(11), 867-74

Alveolar echinococcosis is a serious parasitic disease, leading to large hepatic lesions. It must be distinguished from cystic echinococcosis, or hydatic cyst, caused by Echinococcus granulosus. Early ... [more ▼]

Alveolar echinococcosis is a serious parasitic disease, leading to large hepatic lesions. It must be distinguished from cystic echinococcosis, or hydatic cyst, caused by Echinococcus granulosus. Early diagnosis may allow surgical removal of the lesions by segmental hepatectomy, the only curative treatment. Parasitostatic medical treatment with albendazole may promote stabilization of the disease. Until recently, Belgium was considered a country at very low risk for alveolar echinococcosis, as no human case was reported, despite up to 51% of fox infection in southern Belgium autopsy series. Recently four patients presented with alveolar echinococcosis at the University Hospital Center of Liege, leading to the fear of a possible alveolar echinococcosis endemy in southern Belgium. Two of these patients underwent curative hepatectomy, but the other two had already pulmonary metastases at diagnosis and received palliative albendazole therapy. This article presents these cases, and reviews the clinical features of this parasitic disease. [less ▲]

Clinicopathologic analysis of appendiceal tumors from 1,237 apendectomies

in Acta Gastro-Enterologica Belgica (2005, January), 68(1), 08