Steffen E. Meiler

Curcumin attenuates cerebral edema following traumatic brain injury in mice: a possible role for aquaporin-4?

J. Neurochem. (2010) 113, 637–648.

Pomalidomide augments fetal hemoglobin production without the myelosuppressive effects of hydroxyurea in transgenic sickle cell mice

Pharmacologic induction of fetal hemoglobin (HbF) expression is an effective treatment strategy for sickle cell disease (SCD) and β-thalassemia. Pomalidomide is a potent structural analog of thalidomide and member of a new class of immunomodulatory drugs. Recent reports demonstrated that pomalidomide reduced or eliminated transfusion requirements in certain hematologic malignancies and induced HbF ex vivo in CD34(+) progenitor cells from healthy and SCD donors. We investigated the effects of pomalidomide on erythropoiesis and hemoglobin synthesis in a transgenic mouse model of SCD. We found that 8 weeks of treatment with pomalidomide induced modest increases of HbF with similar efficacy as hydroxyurea. However, in stark contrast to hydroxyureas myelosuppressive effects, pomalidomide augmented erythropoiesis and preserved bone marrow function. Surprisingly, combinatory therapy with both drugs failed to mitigate hydroxyureas myelotoxic effects and caused loss of HbF induction. These findings support further evaluation of pomalidomide as a novel therapy for SCD.

Attenuation of hematoma size and neurological injury with curcumin following intracerebral hemorrhage in mice.

OBJECT Intracerebral hemorrhage (ICH) is associated with significant morbidity and mortality. Acute hematoma enlargement is an important predictor of neurological injury and poor clinical prognosis; but neurosurgical clot evacuation may not be feasible in all patients and treatment options remain largely supportive. Thus, novel therapeutic approaches to promote hematoma resolution are needed. In the present study, the authors investigated whether the curry spice curcumin limited neurovascular injury following ICH in mice. METHODS Intracerebral hemorrhage was induced in adult male CD-1 mice by intracerebral administration of collagenase or autologous blood. Clinically relevant doses of curcumin (75-300 mg/kg) were administered up to 6 hours after ICH, and hematoma volume, inflammatory gene expression, blood-brain barrier permeability, and brain edema were assessed over the first 72 hours. Neurological assessments were performed to correlate neurovascular protection with functional outcomes. RESULTS Curcumin increased hematoma resolution at 72 hours post-ICH. This effect was associated with a significant reduction in the expression of the proinflammatory mediators, tumor necrosis factor-α, interleukin-6, and interleukin-1β. Curcumin also reduced disruption of the blood-brain barrier and attenuated the formation of vasogenic edema following ICH. Consistent with the reduction in neuroinflammation and neurovascular injury, curcumin significantly improved neurological outcome scores after ICH. CONCLUSIONS Curcumin promoted hematoma resolution and limited neurological injury following ICH. These data may indicate clinical utility for curcumin as an adjunct therapy to reduce brain injury and improve patient outcome.

Receptor-mediated delivery of engineered nucleases for genome modification

Engineered nucleases, which incise the genome at predetermined sites, have a number of laboratory and clinical applications. There is, however, a need for better methods for controlled intracellular delivery of nucleases. Here, we demonstrate a method for ligand-mediated delivery of zinc finger nucleases (ZFN) proteins using transferrin receptor-mediated endocytosis. Uptake is rapid and efficient in established mammalian cell lines and in primary cells, including mouse and human hematopoietic stem-progenitor cell populations. In contrast to cDNA expression, ZFN protein levels decline rapidly following internalization, affording better temporal control of nuclease activity. We show that transferrin-mediated ZFN uptake leads to site-specific in situ cleavage of the target locus. Additionally, despite the much shorter duration of ZFN activity, the efficiency of gene correction approaches that seen with cDNA-mediated expression. The approach is flexible and general, with the potential for extension to other targeting ligands and nuclease architectures.

Design, synthesis, and pharmacological evaluation of novel hybrid compounds to treat sickle cell disease symptoms.

A novel series of thalidomide derivatives (4a-f) designed by molecular hybridization were synthesized and evaluated in vitro and in vivo for their potential use in the oral treatment of sickle cell disease symptoms. Compounds 4a-f demonstrated analgesic, anti-inflammatory, and NO-donor properties. Compounds 4c and 4d were considered promising candidate drugs and were further evaluated in transgenic sickle cell mice to determine their capacity to reduce the levels of the proinflammatory cytokine tumor necrosis factor α (TNFα). Unlike hydroxyurea, the compounds reduced the concentrations of TNFα to levels similar to those induced with the control dexamethasone (300 μmol/kg). These compounds are novel lead drug candidates with multiple beneficial actions in the treatment of sickle cell disease symptoms and offer an alternative to hydroxyurea treatment.

CURCUMIN ATTENUATES HEMATOMA SIZE AND NEUROLOGICAL INJURY FOLLOWING INTRACEREBRAL HEMORRHAGE IN MICE

OBJECT Intracerebral hemorrhage (ICH) is associated with significant morbidity and mortality. Acute hematoma enlargement is an important predictor of neurological injury and poor clinical prognosis; but neurosurgical clot evacuation may not be feasible in all patients and treatment options remain largely supportive. Thus, novel therapeutic approaches to promote hematoma resolution are needed. In the present study, the authors investigated whether the curry spice curcumin limited neurovascular injury following ICH in mice. METHODS Intracerebral hemorrhage was induced in adult male CD-1 mice by intracerebral administration of collagenase or autologous blood. Clinically relevant doses of curcumin (75-300 mg/kg) were administered up to 6 hours after ICH, and hematoma volume, inflammatory gene expression, blood-brain barrier permeability, and brain edema were assessed over the first 72 hours. Neurological assessments were performed to correlate neurovascular protection with functional outcomes. RESULTS Curcumin increased hematoma resolution at 72 hours post-ICH. This effect was associated with a significant reduction in the expression of the proinflammatory mediators, tumor necrosis factor-α, interleukin-6, and interleukin-1β. Curcumin also reduced disruption of the blood-brain barrier and attenuated the formation of vasogenic edema following ICH. Consistent with the reduction in neuroinflammation and neurovascular injury, curcumin significantly improved neurological outcome scores after ICH. CONCLUSIONS Curcumin promoted hematoma resolution and limited neurological injury following ICH. These data may indicate clinical utility for curcumin as an adjunct therapy to reduce brain injury and improve patient outcome.

Endothelin-1 contributes to the progression of renal injury in sickle cell disease via reactive oxygen species

Endothelin‐1 (ET‐1) is increased in patients with sickle cell disease and may contribute to the development of sickle cell nephropathy. The current study was designed to determine whether ET‐1 acting via the ETA receptor contributes to renal injury in a mouse model of sickle cell disease.

Hb M Dothan [β 25/26 (B7/B8)/(GGT/GAG→GAG//Gly/Glu→Glu]; a new mechanism of unstable methemoglobin variant and molecular characteristics

A new unstable beta globin chain variant associated with methemoglobin (Met-Hb) phenotype was found in a Caucasian infant. Molecular analysis of the beta globin gene using polymerase chain reaction (PCR) amplification and sequencing led to the detection of a new in frame deletion in exon-1. Direct sequencing of the PCR product revealed a 3 bp deletion (-GTG) between codons 25/26, which resulted in the loss of a single amino acid (-Gly). We propose that this newly discovered unstable M-hemoglobin (M-Hb) variant, named Hb Dothan [GGT/GAG-->GAG//Gly/Glu-->Glu], is caused by a shift in the amino acid sequence and altered packing of the B and E helices during beta globin synthesis, and also changes the orientation of the critical proximal and distal histidine in the F and E helices respectively. Phenotype/Genotype features and molecular characteristics of this new beta chain are presented in this communication.

Ventilatory techniques for central airway obstruction.

INTRODUCTION Central airway obstruction (CAO) refers to obstruction involving the trachea, mainstem, or lobar bronchi. These lesions can be either benign or malignant. Obstruction of these areas may lead to dyspnea, atelectasis, post-obstructive pneumonia, and death. Treatment options to relieve CAO include airway dilation, laser techniques, cryotherapy, and stenting. CAO is becoming more prevalent due to our aging population and increase in life expectancy. Otolaryngologists are increasingly called upon to manage these patients; therefore, it is important to know the various options available to control the airway and ventilate patients with CAO. Traditionally, CAO is managed either by flexible or rigid bronchoscopy. Flexible bronchoscopy has the advantage of the patient being awake; however, the scope partially occludes the lumen. Rigid bronchoscopy requires general anesthesia, but does not occlude the lumen, which allows for ventilation and easier control of hemorrhage into the airway. Jet ventilation is based on delivery of gas under high pressure through an unblocked catheter into the airway, which is open to ambient air. Jet ventilation allows for an unobstructed view of the airway. Jet ventilation can be performed supraglottically (above the glottis) or subglottically (below the glottis). High-frequency jet ventilation is the delivery of small tidal volumes at higher than physiological rates followed by passive expiration (Table I).

Thalassemia-like phenotype in a novel complex hemoglobinopathy with α, β, δ globin chain abnormalities.

The occurrence of multiple abnormalities of &agr;, &bgr;, &dgr;, and &ggr; globin genes may lead to unusual and complex phenotypes when they arise simultaneously in the same individual. Here, we report the findings of an African American boy who coinherited 3 heterozygous globin gene abnormalities: the unstable &bgr;-globin chain variant; hemoglobin (Hb) Showa-Yakushiji [&bgr;110(G12) Leu→Pro], the &dgr;-globin chain variant; HbB2 [&dgr;16(A13) Gly→Arg] and &agr;+-thalassemia (&agr;+-thal); (&agr;-3.7/&agr;&agr;). Hb Showa-Yakushiji had been previously described in Japanese, Indian, and European populations. We report its first occurrence in a child of African ancestry who presented with anemia not responsive to iron and an incomplete &bgr;-thalassemia minor phenotype. Although the clinical and laboratory features of Hb Showa-Yakushiji mimic those of a &bgr;-thalassemia, the coinheritance of the &dgr;-globin chain variant Hb B2 suppressed the relative increase in Hb A2 usually observed in heterozygotes for the Hb Showa-Yakushiji mutation. Protein-based methods detected only a trace amount of HbB2 and failed to reveal presence of Hb Showa-Yakushiji and &agr;+-thal. The latter were only identified through DNA analyses. The diagnostic difficulties, molecular characteristics, and genotype/phenotype correlations of this novel complex hemoglobinopathy syndrome are reviewed.