Effect of hydroxyurea exposure before puberty on sperm parameters in males with sickle cell disease.

Sperm parameters are known to be impaired in men with sickle cell disease (SCD). Although treatment with hydroxyurea (HU) has an impact on sperm quality, sperm preservation is impossible before puberty. This study's primary objective was to analyze and compare sperm parameters in male patients with SCD exposed (or not) to HU before puberty. Twenty-six sperm samples from 15 patients (median age, 17 years; range, 16-23) treated with HU during childhood were compared with 46 samples from 23 HU-naïve patients (20 years; 16-24). The median age at HU initiation was 6 years (1-14 years), the median duration of HU treatment was 4 years (0.5-10), and the mean dose of HU was 22.4 ± 3.7 mg/kg per day. Although we observed substantial quantitative and qualitative semen abnormalities in all patients, there were no significant differences in semen volume, sperm concentration, total sperm count, or spermatozoa motility, morphology, and vitality between the HU-exposed and HU-naïve groups. At the time of the semen analysis, 100% of the patients in the HU-exposed group and 52% of the patients in the HU-naïve group received transfusion therapy. The specific effect of HU on spermatogenesis in very young infants and the putative value of transfusion for reversing the toxicity of HU warrant further investigation.

Indications and outcome of splenectomy in hematologic disease.

Splenectomy is part of the therapeutic arsenal for benign or malignant hematological disorders that constitute the main indication for elective splenectomy. With the development of minimally invasive approaches, and in particular, laparoscopy, as well as the advent of monoclonal antibody therapy, the indications and the outcomes of splenectomy for hematologic disease have changed in recent years. Nonetheless, splenectomy has its place in hemoglobinopathies and hemolytic diseases, improves thrombocytopenia in refractory immune thrombocytopenic purpura, can reverse sequelae linked to voluminous splenomegaly secondary to myelofibrosis, or can be used for diagnostic purposes or for splenomegaly in lymphoproliferative syndromes.

[French guidelines for the management of adult sickle cell disease: 2015 update]. / Recommandations françaises de prise en charge de la drépanocytose de l'adulte: actualisation 2015.

Sickle cell disease is a systemic genetic disorder, causing many functional and tissular modifications. As the prevalence of patients with sickle cell disease increases gradually in France, every physician can be potentially involved in the care of these patients. Complications of sickle cell disease can be acute and chronic. Pain is the main symptom and should be treated quickly and aggressively. In order to reduce the fatality rate associated with acute chest syndrome, it must be detected and treated early. Chronic complications are one of the main concerns in adults and should be identified as early as possible in order to prevent end organ damage. Many organs can be involved, including bones, kidneys, eyes, lungs, etc. The indications for a specific treatment (blood transfusion or hydroxyurea) should be regularly discussed. Coordinated health care should be carefully organized to allow a regular follow-up near the living place and access to specialized departments. We present in this article the French guidelines for the sickle cell disease management in adulthood.

[HSP70, an erythropoiesis regulator that determines the fate of erythroblasts between death and differentiation]. / HSP70 un régulateur de l'érythropoïèse qui détermine le destin des érythroblastes entre mort et différenciation.

Erythropoiesis is finely regulated by two major cytokines, stem cell factor (SCF) and erythropoietin (Epo). Decrease levels of Epo result in caspase activation and erythroid progenitors apoptosis. However, normal erythroid cell maturation requests caspase activation and cleavage of various caspase substrates, except the erythroid transcription factor GATA-1, that is protected by interaction with the chaperone HSP70 in the nucleus. Therefore, molecular abnormalities associated with decrease of HSP70 expression in the nucleus may result in ineffective erythropoiesis characterized by apoptosis and impaired maturation of erythroid precursors. These findings open new potential targeted therapies for erythroid disorders.

Extensive chronic GVHD is associated with donor blood CD34+ cell count after G-CSF mobilization in non-myeloablative allogeneic PBSC transplantation.

The correlation between the incidence of GVHD and the number of infused CD34(+) cells remains controversial for PBSC transplantation after a reduced-intensity-conditioning (RIC) regimen. We evaluated 99 patients transplanted with an HLA-identical sibling after the same RIC (2-Gy-TBI/fludarabine). Donor and recipient characteristics, donor's blood G-CSF-mobilized CD34(+) cell count, and number of infused CD34(+) and CD3(+) cells were analyzed as risk factors for acute and chronic GVHD There was a trend for an increased incidence of extensive chronic GVHD in the quartile of patients receiving more than 10 × 10(6) CD34(+) cells/kg (P = 0.05). Interestingly, the number of donor's blood CD34(+) cells at day 5 of G-CSF mobilization was closely associated with the incidence of extensive chronic GVHD, that is, 48% (95% CI: 28-68) at 24-months in the quartile of patients whose donors had the highest CD34(+) cell counts versus 24.3% (95% CI: 14-34) in the other patients (P = 0.007). In multivariate analysis, the only factor correlating with extensive chronic GVHD (cGVHD) was the donor's blood CD34(+) cell count after G-CSF (HR 2.49; 95% CI: 1.16-5.35, P = 0.019). This study shows that the incidence of cGVHD is more strongly associated with the donor's ability to mobilize CD34(+) cells than with the number of infused CD34(+) cells.

[Hyperuricemia in sickle cell disease in France]. / Hyperuricémie chez les patients drépanocytaires suivis en France.

PURPOSE: Hyperuricemia has been reported to be a common feature of sickle cell disease occurring between 32 to 41% of the patients, in studies conducted during the 1970's. Since then, this notion has been rarely challenged. The objective of this study was to assess the prevalence of hyperuricemia and gout in adult patients with sickle cell disease in France. METHODS: Between May 2007 and March 2009, serum and urinary urate concentration, creatininemia and hemogram were prospectively assessed in all consecutive sickle cell patients, followed in our sickle cell disease centre. All subjects were in a clinically steady state. Clinical acute gout history was also recorded. RESULTS: Sixty-five patients (mean age 31±10.3 years) were investigated. Mean uric acid serum level was 281.6±74µmol/L. Hyperuricemia was evidenced in six patients only (9.2%) (95% IC: 3.5-19.0). None of the patient had a medical history of acute gout. Patients in the higher serum uric acid tertile concentration had higher serum creatinine level (62.3±17.1µmol/L vs 51.5±12.6µmol/L, P<0.01), lower fractional excretion of urate (4.5% vs 6.8%, P<0.03) and higher reticulocyte count (median 219500/mm(3) vs 144000/mm(3), P=0.08) compared to the other patients. CONCLUSION: Hyperuricemia and gout are not a clinical problem in sickle cell disease in our country. Nevertheless, our findings indicate that kidney function has to be fully explored if serum uric acid level is elevated or significantly deteriorates during follow-up. Serum uric acid level could be an early marker of renal dysfunction in sickle cell disease patients.

Caspase-activated ROCK-1 allows erythroblast terminal maturation independently of cytokine-induced Rho signaling.

Stem cell factor (SCF) and erythropoietin are strictly required for preventing apoptosis and stimulating proliferation, allowing the differentiation of erythroid precursors from colony-forming unit-E to the polychromatophilic stage. In contrast, terminal maturation to generate reticulocytes occurs independently of cytokine signaling by a mechanism not fully understood. Terminal differentiation is characterized by a sequence of morphological changes including a progressive decrease in cell size, chromatin condensation in the nucleus and disappearance of organelles, which requires transient caspase activation. These events are followed by nucleus extrusion as a consequence of plasma membrane and cytoskeleton reorganization. Here, we show that in early step, SCF stimulates the Rho/ROCK pathway until the basophilic stage. Thereafter, ROCK-1 is activated independently of Rho signaling by caspase-3-mediated cleavage, allowing terminal maturation at least in part through phosphorylation of the light chain of myosin II. Therefore, in this differentiation system, final maturation occurs independently of SCF signaling through caspase-induced ROCK-1 kinase activation.

[Guidelines for management of adult sickle cell disease]. / Recommandations pratiques de prise en charge de la drépanocytose de l'adulte.

Sickle cell disease is a systemic disease that can potentially involve all organs. As the prevalence of patients with sickle cell disease increases gradually in France, every physician can be potentially involved in the care of these patients. Complications of sickle cell disease can be acute or chronic. Pain is the main symptom and should be treated quickly and aggressively. Acute chest syndrome is the leading cause of acute death and must be prevented, detected, and treated without delay. Chronic complications are one of the main concerns in adults and should be identified as early as possible in order to prevent sequels. Many organs can be involved, including the bones, kidneys, eyes, lungs... The indications for a specific treatment (blood transfusion or hydroxyurea) should be discussed. Health care should be carefully organized to allow both a regular follow-up near the living place and access to specialized departments. We present in this article the French guidelines for the sickle cell disease management in adulthood.

Overexpression of the heat-shock protein 70 is associated to imatinib resistance in chronic myeloid leukemia.

Imatinib is an effective therapy for chronic myeloid leukemia (CML), a myeloproliferative disorder characterized by the expression of the recombinant oncoprotein Bcr-Abl. In this investigation, we studied an imatinib-resistant cell line (K562-r) generated from the K562 cell line in which none of the previously described mechanisms of resistance had been detected. A threefold increase in the expression of the heat-shock protein 70 (Hsp70) was detected in these cells. This increase was not associated to heat-shock transcription factor-1 (HSF-1) overexpression or activation. RNA silencing of Hsp70 decreased dramatically its expression (90%), and was accompanied by a 34% reduction in cell viability. Overexpression of Hsp70 in the imatinib-sensitive K562 line induced resistance to imatinib as detected by a large reduction in cell death in the presence of 1 muM of imatinib. Hsp70 level was also increased in blast cells of CML patients resistant to imatinib, whereas the level remained low in responding patients. Taken together, the results demonstrate that overexpression of Hsp70 can lead to both in vitro and in vivo resistance to imatinib in CML cells. Moreover, the overexpression of Hsp70 detected in imatinib-resistant CML patients supports this mechanism and identifies potentially a marker and a therapeutic target of CML evolution.

The VAD chemotherapy regimen plus a G-CSF dose of 10 microg/kg is as effective and less toxic than high-dose cyclophosphamide plus a G-CSF dose of 5 microg/kg for progenitor cell mobilization: results from a monocentric study of 82 patients.

A study was conducted to compare the efficiency and toxicity of two peripheral blood stem cell (PBSC) mobilization procedures for newly diagnosed patients with multiple myeloma. Patients from group 1 (n=51) were treated by high-dose cyclophosphamide (HD-CY) plus G-CSF (5 microg/kg/day), and the second group (n=31) by VAD regimen plus G-CSF administration (10 microg/kg/day). Successful mobilization, defined by a minimal count of 2.5 x 10(6) CD34(+) cells/kg collected, was achieved in 96 and 90% of patients in groups 1 and 2, respectively (P=0.15). The mean peripheral blood CD34(+) cells concentration and the mean CD34(+) cells/kg collected were higher in group 2 than in the group 1 (P=0.05). The mean number of leukaphereses necessary to collect a count of 2.5 x 10(6) CD34(+) cells/kg was reduced in group 2 compared to group 1. Adverse events, blood products consumption and time spent in the hospital were significantly greater after HD-CY. In conclusion, VAD plus a G-CSF dose of 10 microg/kg administration seems preferential to HD-CY plus a G-CSF dose of 5 microg/kg for PBSC collection because of equivalent or better efficiency in stem cell mobilization, strong favorable toxicity profile and reduced cost.

[Erythropoiesis: a paradigm for the role of caspases in cell death and differentiation]. / L'erythropoïèse : un paradigme pour l'etude du rôle des caspases dans la mort et la différenciation cellulaire.

Erythroid differentiation involves the transcription factor GATA-1 that positively regulates promoters of erythroid genes (including haemoglobin, glycophorin, erythropoietin receptor) and of erythropoietin. Terminal erythroid differentiation is characterized by major morphological changes that include chromatin condensation and cell size reduction. The morphological changes are partially similar at least to those observed during apoptosis. The production of red cells depends on the apoptosis rate of erythroid progenitors and precursors. Upon erythropoietin starvation or engagement of the death receptor Fas, caspases are activated in erythroid precursors and cleave GATA-1, thus inducing maturation arrest and apoptosis of immature erythroblasts. We have recently demonstrated that, upon erythropoietin stimulation, caspase-3 was also activated, an event required for human terminal erythroblast maturation. Proteins cleaved by caspases in erythroid cells undergoing terminal differentiation include Lamin B and Acinus, which are involved in chromatin condensation. In contrast, despite caspase-3 activation neither GATA-1 degradation nor apoptosis was observed. Thus, the fate of erythroid precursors is determined downstream of caspase activation by the pattern of cleaved targets. Therefore, there are some mechanisms underlying the selective protection of caspase-3 targets during erythropoiesis. This model in which caspases activation is required for differentiation may apply to other haematopoietic or non haematopoietic cellular systems which are described in this review.