Defining the phenotypes of sickle cell disease.

The sickle cell gene is pleiotropic in nature. Although it is a single gene mutation, it has multiple phenotypic expressions that constitute the complications of sickle cell disease. The frequency and severity of these complications vary considerably both latitudinally in patients and longitudinally in the same patient over time. Thus, complications that occur in childhood may disappear, persist or get worse with age. Dactylitis and stroke, for example, occur mostly in childhood, whereas leg ulcers and renal failure typically occur in adults. It is essential that the phenotypic manifestations of sickle cell disease be defined accurately so that communication among providers and researchers facilitates the implementation of appropriate and cost-effective diagnostic and therapeutic modalities. The aim of this review is to define the complications that are specific to sickle cell disease based on available evidence in the literature and the experience of hematologists in this field

Factors associated with hospital readmission in sickle cell disease

<p>Abstract</p> <p>Background</p> <p>Sickle cell disease is the most frequent hereditary disease in Brazil, and people with the disease may be hospitalised several times in the course of their lives. The purpose of this study was to estimate the hazard ratios of factors associated with the time between hospital admissions.</p> <p>Methods</p> <p>The study sample comprised all patients admitted, from 2000 to 2004, to a university hospital in Rio de Janeiro State, south-east Brazil, as a result of acute complications from sickle cell disease (SCD). Considering the statistical problem of studying individuals with multiple events over time, the following extensions of Cox's proportional hazard ratio model were compared: the independent increment marginal model (Andersen-Gill) and the random effects model.</p> <p>Results</p> <p>The study considered 71 patients, who were admitted 223 times for acute events related to SCD. The hazard ratios for hospital readmission were statistically significant for the prior occurrence of vaso-occlusive crisis and development of renal failure. However, analysis of residuals of the marginal model revealed evidence of non-proportionality for some covariates.</p> <p>Conclusion</p> <p>the results from applying the two models were generally similar, indicating that the findings are not highly sensitive to different approaches. The better fit by the frailty model suggests that there are unmeasured individual factors with impact on hospital readmission.</p

Hydroxyurea and sickle cell anemia: effect on quality of life

BACKGROUND: The Multicenter Study of Hydroxyurea (HU) in Sickle Cell Anemia (MSH) previously showed that daily oral HU reduces painful sickle cell (SS) crises by 50% in patients with moderate to severe disease. The morbidity associated with this disease is known to have serious negative impact on the overall quality of life(QOL) of affected individuals. METHODS: The data in this report were collected from the 299 patients enrolled in the MSH. Health quality of llife (HQOL) measures were assessed in the MSH as a secondary endpoint to determine if the clinical benefit of HU could translate into a measurable benefit perceptible to the patients. HQOL was assessed with the Profile of Mood States, the Health Status Short Form 36 (SF-36), including 4-week pain recall, and the Ladder of Life, self-administered twice 2-weeks apart pre-treatment and every 6 months during the two-year, randomized, double-blind, treatment phase. The effects of factors including randomized treatment, age, gender, pre-treatment crises frequency, Hb-F level mean, daily pain from 4-week pre-treatment diaries, and 2-year Hb-F response level (low or high) were investigated. RESULTS: Over two years of treatment, the benefit of HU treatment on QOL, other than pain scales, was limited to those patients taking HU who maintained a high HbF response, compared to those with low HbF response or on placebo. These restricted benefits occurred in social function, pain recall and general health perception. Stratification according to average daily pain prior to treatment showed that responders to HU whose average daily pain score was 5–9 (substantial pain) achieved significant reduction in the tension scale compared to the placebo group and to non-responders. HU had no apparent effect on other QOL measures. CONCLUSION: Treatment of SS with HU improves some aspects of QOL in adult patients who already suffer from moderate-to-severe SS

Aged garlic extract therapy for sickle cell anemia patients

BACKGROUND: Sickle cell anemia is one of the most prevalent hereditary disorders with prominent morbidity and mortality. With this disorder oxidative, phenomena play a significant role in its pathophysiology. One of the garlic (Allium sativum L.) formulations, aged garlic extract (AGE), has been reported to exert an anti-oxidant effect in vitro, we have evaluated the anti-oxidant effect of AGE on sickle red blood cells (RBC). METHODS: Five patients (two men and three women, mean age 40 ± 15 years, range 24–58 years) with sickle cell anemia participated in the study. AGE was administered at a dose of 5 ml a day. Whole blood samples were obtained at baseline and at 4 weeks for primarily Heinz body analysis. RESULTS: The data were consistent with our hypothesis. In all patients, the number of Heinz bodies decreased over the 4 week period (58.9 ± 20.0% at baseline to 29.8 ± 15.3% at follow-up, p = 0.03). CONCLUSIONS: These data suggest that there is a significant anti-oxidant activity of AGE on sickle RBC. AGE may be further evaluated as a potential therapeutic agent to ameliorate complications of sickle cell anemia

Membrane Sealant Poloxamer P188 Protects Against Isoproterenol Induced Cardiomyopathy in Dystrophin Deficient Mice

<p>Abstract</p> <p>Background</p> <p>Cardiomyopathy in Duchenne muscular dystrophy (DMD) is an increasing cause of death in patients. The absence of dystrophin leads to loss of membrane integrity, cell death and fibrosis in cardiac muscle. Treatment of cardiomyocyte membrane instability could help prevent cardiomyopathy.</p> <p>Methods</p> <p>Three month old female mdx mice were exposed to the β₁receptor agonist isoproterenol subcutaneously and treated with the non-ionic tri-block copolymer Poloxamer P188 (P188) (460 mg/kg/dose i.p. daily). Cardiac function was assessed using high frequency echocardiography. Tissue was evaluated with Evans Blue Dye (EBD) and picrosirius red staining.</p> <p>Results</p> <p>BL10 control mice tolerated 30 mg/kg/day of isoproterenol for 4 weeks while death occurred in mdx mice at 30, 15, 10, 5 and 1 mg/kg/day within 24 hours. Mdx mice tolerated a low dose of 0.5 mg/kg/day. Isoproterenol exposed mdx mice showed significantly increased heart rates (p < 0.02) and cardiac fibrosis (p < 0.01) over 4 weeks compared to unexposed controls. P188 treatment of mdx mice significantly increased heart rate (median 593 vs. 667 bpm; p < 0.001) after 2 weeks and prevented a decrease in cardiac function in isoproterenol exposed mice (Shortening Fraction = 46 ± 6% vs. 35 ± 6%; p = 0.007) after 4 weeks. P188 treated mdx mice did not show significant differences in cardiac fibrosis, but demonstrated significantly increased EBD positive fibers.</p> <p>Conclusions</p> <p>This model suggests that chronic intermittent intraperitoneal P188 treatment can prevent isoproterenol induced cardiomyopathy in dystrophin deficient mdx mice.</p

Rest-Mediated Regulation of Extracellular Matrix Is Crucial for Neural Development

Neural development from blastocysts is strictly controlled by intricate transcriptional programmes that initiate the down-regulation of pluripotent genes, Oct4, Nanog and Rex1 in blastocysts followed by up-regulation of lineage-specific genes as neural development proceeds. Here, we demonstrate that the expression pattern of the transcription factor Rest mirrors those of pluripotent genes during neural development from embryonic stem (ES) cells and an early abrogation of Rest in ES cells using a combination of gene targeting and RNAi approaches causes defects in this process. Specifically, Rest ablation does not alter ES cell pluripotency, but impedes the production of Nestin+ neural stem cells, neural progenitor cells and neurons, and results in defective adhesion, decrease in cell proliferation, increase in cell death and neuronal phenotypic defects typified by a reduction in migration and neurite elaboration. We also show that these Rest-null phenotypes are due to the dysregulation of its direct or indirect target genes, Lama1, Lamb1, Lamc1 and Lama2 and that these aberrant phenotypes can be rescued by laminins

Effects of Long-Term Space Flight on Erythrocytes and Oxidative Stress of Rodents

Erythrocyte and hemoglobin losses have been frequently observed in humans during space missions; these observations have been designated as “space anemia”. Erythrocytes exposed to microgravity have a modified rheology and undergo hemolysis to a greater extent. Cell membrane composition plays an important role in determining erythrocyte resistance to mechanical stress and it is well known that membrane composition might be influenced by external events, such as hypothermia, hypoxia or gravitational strength variations. Moreover, an altered cell membrane composition, in particular in fatty acids, can cause a greater sensitivity to peroxidative stress, with increase in membrane fragility. Solar radiation or low wavelength electromagnetic radiations (such as gamma rays) from the Earth or the space environment can split water to generate the hydroxyl radical, very reactive at the site of its formation, which can initiate chain reactions leading to lipid peroxidation. These reactive free radicals can react with the non-radical molecules, leading to oxidative damage of lipids, proteins and DNA, etiologically associated with various diseases and morbidities such as cancer, cell degeneration, and inflammation. Indeed, radiation constitutes on of the most important hazard for humans during long-term space flights. With this background, we participated to the MDS tissue-sharing program performing analyses on mice erythrocytes flown on the ISS from August to November 2009. Our results indicate that space flight induced modifications in cell membrane composition and increase of lipid peroxidation products, in mouse erythrocytes. Moreover, antioxidant defenses in the flight erythrocytes were induced, with a significant increase of glutathione content as compared to both vivarium and ground control erythrocytes. Nonetheless, this induction was not sufficient to prevent damages caused by oxidative stress. Future experiments should provide information helpful to reduce the effects of oxidative stress exposure and space anemia, possibly by integrating appropriate dietary elements and natural compounds that could act as antioxidants