Christopher Leveque

BET Protein Antagonist JQ1 Is Synergistically Lethal with FLT3 Tyrosine Kinase Inhibitor (TKI) and Overcomes Resistance to FLT3-TKI in AML Cells Expressing FLT-ITD

Recently, treatment with bromodomain and extraterminal protein antagonist (BA) such as JQ1 has been shown to inhibit growth and induce apoptosis of human acute myelogenous leukemia (AML) cells, including those expressing FLT3-ITD. Here, we demonstrate that cotreatment with JQ1 and the FLT3 tyrosine kinase inhibitor (TKI) ponatinib or AC220 synergistically induce apoptosis of cultured and primary CD34+ human AML blast progenitor cells (BPC) expressing FLT3-ITD. Concomitantly, as compared with each agent alone, cotreatment with JQ1 and the FLT3-TKI caused greater attenuation of c-MYC, BCL2, and CDK4/6. Simultaneously, cotreatment with JQ1 and the FLT3-TKI increased the levels of p21, BIM, and cleaved PARP, as well as mediated marked attenuation of p-STAT5, p-AKT, and p-ERK1/2 levels in AML BPCs. Conversely, cotreatment with JQ1 and FLT3-TKI was significantly less active against CD34+ normal bone marrow progenitor cells. Knockdown of BRD4 by short hairpin RNA also sensitized AML cells to FLT3-TKI. JQ1 treatment induced apoptosis of mouse Ba/F3 cells ectopically expressing FLT3-ITD with or without FLT3-TKI–resistant mutations F691L and D835V. Compared with the parental human AML FLT3-ITD–expressing MOLM13, MOLM13-TKIR cells resistant to AC220 were markedly more sensitive to JQ1-induced apoptosis. Furthermore, cotreatment with JQ1 and the pan-histone deacetylase inhibitor (HDI) panobinostat synergistically induced apoptosis of FLT3-TKI–resistant MOLM13-TKIR and MV4-11-TKIR cells. Collectively, these findings support the rationale for determining the in vivo activity of combined therapy with BA and FLT3-TKI against human AML cells expressing FLT3-ITD or with BA and HDI against AML cells resistant to FLT3-TKI. Mol Cancer Ther; 13(10); 2315–27. ©2014 AACR.

Retrograde cerebral perfusion during profound hypothermia and circulatory arrest in pigs

The purpose of this study was to evaluate the use of retrograde cerebral perfusion via the superior vena cava during profound hypothermia and circulatory arrest (CA) in pigs. In three groups of 5 pigs each, group A (control) underwent cardiopulmonary bypass and normothermic CA for 1 hour, group B underwent cardiopulmonary bypass, profound hypothermia, and CA (15 degrees C nasopharyngeal) for 1 hour, and group C underwent the same procedure as group B plus retrograde cerebral perfusion. In group A none awoke. In group B, 2 of 5 did not awake and 3 of 5 awoke unable to stand, 2 with perceptive hind limb movement and 1 moving all extremities. In group C all awoke, 4 of 5 able to stand and 1 of 5 unable to stand but moving all limbs. In neurologic evaluation group B had significantly lower Tarlov scores than group C (p = 0.0090). Group B mean wake-up time, plus or minus standard error of the mean, was 124.6 +/- 4.6 minutes versus 29.2 +/- 5.1 in group C (p = 0.0090). In group B late phase CA cerebral blood flow dropped 30.9% +/- 4.8%, but in group C it rose 24.7% +/- 9.3% (p = 0.0007, pooled variance t test, two-tailed). In group B late phase CA brain oxygenation decreased 46.0% +/- 13.9% but it increased 26.1% +/- 5.4% in group C (p = 0.0013). This difference was reduced somewhat during rewarming (B, -21.2% +/- 14.9%; C, 16.4% +/- 4.7%; p = 0.043). Group B rewarming jugular venous O2 saturation was 30.8% +/- 2.5% versus 56.0% +/- 4.4% in group C (p = 0.0011). We conclude that in pigs retrograde cerebral perfusion combined with profound hypothermia during CA significantly reduces neurologic dysfunction, providing superior brain protection.

Pre-clinical efficacy of combined therapy with novel β-catenin antagonist BC2059 and histone deacetylase inhibitor against AML cells

The canonical wingless-type MMTV integration site (WNT)-β-catenin pathway is essential for self-renewal, growth and survival of acute myeloid leukemia (AML) stem/blast progenitor cells (BPCs). Deregulated WNT signaling inhibits degradation of β-catenin, causing increased nuclear translocation and co-factor activity of β-catenin with the transcriptional regulator T-cell factor (TCF) 4/lymphoid enhancer factor 1 in AML BPCs. Here, we determined the pre-clinical anti-AML activity of the anthraquinone oxime-analog BC2059 (BC), known to attenuate β-catenin levels. BC treatment disrupted the binding of β-catenin with the scaffold protein transducin β-like 1 and proteasomal degradation and decline in the nuclear levels of β-catenin. This was associated with reduced transcriptional activity of TCF4 and expression of its target genes, cyclin D1, c-MYC and survivin. BC treatment dose-dependently induced apoptosis of cultured and primary AML BPCs. Treatment with BC also significantly improved the median survival of immune-depleted mice engrafted with either cultured or primary AML BPCs, exhibiting nuclear expression of β-catenin. Co-treatment with the pan-histone deacetylase inhibitor panobinostat and BC synergistically induced apoptosis of cultured and primary AML BPCs, including those expressing FLT3-ITD, as well as further significantly improved the survival of immune-depleted mice engrafted with primary AML BPCs. These findings underscore the promising pre-clinical activity and warrant further testing of BC against human AML, especially those expressing FLT3-ITD.

Therapeutic plasma exchange a potential strategy for patients with advanced heart failure

Background: Previous reports had emphasized the importance of humoral immunity in heart failure in humans, primarily determined by the presence of circulating antibodies. However, there is little or no information about the frequency of anticardiac antibodies present in failing human myocardium. Methods: Clinical data and myocardial tissue samples were analyzed to determine the role of humoral immunity in patients with chronic heart failure (CHF) in different settings. Results: Anticardiac antibodies were found present in failing hearts but not in normal control hearts. Further, the level of expression of these anticardiac antibodies changed with the severity of the disease state; and in patients with acute heart failure, we found selective activation of B cells. Finally, treatment of CHF patients with therapeutic plasma exchange, a strategy that removes circulating antibodies, resulted in a reduction in anticardiac antibody deposition and improvements in cardiac function. Conclusion: These data collectively suggest a role of humoral immunity in the progression of heart failure. J. Clin. Apheresis, 2010.

Ultrasound-guided peripheral venous access for therapeutic apheresis procedures reduces need for central venous catheters.

Therapeutic and donor apheresis requires adequate vascular access to achieve inlet flow rates of ∼50—100 mL/min. While central dialysis‐type venous catheters can usually provide such access, their use includes several associated risks. Some of these risks can be avoided or diminished if adequate peripheral venous access can be established. Some patients have adequate peripheral veins for apheresis that cannot be readily identified visually or by palpation. We hypothesized that ultrasound‐guided peripheral venous access would benefit such patients and would lead to placement of fewer central venous catheters. The technique of ultrasound‐guided peripheral access for apheresis has been in use at Houston Methodist Hospital since 2012. We performed a prospective review of patients undergoing inpatient and outpatient apheresis at Houston Methodist Hospital from July 1, 2015 to September 30, 2015, to assess its benefit. During this time, we performed 831 procedures on 186 patients, including 787 therapeutic plasma exchanges, three red blood cell exchanges, 41 peripheral stem cell collections. Ultrasound‐guided vascular access was used for 68 procedures (8% of all procedures), including 62 therapeutic plasma exchanges, 4 peripheral stem cell collections, and 2 red blood cell changes. Use of ultrasound‐guided peripheral access prevented the placement of central venous catheters in 37 (20%) patients, demonstrating its utility in a busy transfusion service.

Impact of intraoperative factor concentrates on blood product transfusions during orthotopic liver transplantation

Major bleeding in orthotopic liver transplantation is associated with significant morbidity and mortality. Limited literature exists regarding comparative effectiveness of prothrombin complex concentrate and fibrinogen concentrate during orthotopic liver transplantation on blood product utilization.

Leukapheresis reduces 4-week mortality in acute myeloid leukemia patients with hyperleukocytosis - a retrospective study from a tertiary center.

Abstract Hyperleukocytosis in patients with acute myeloid leukemia (AML) can lead to leukostasis, which if left untreated, has a high mortality. While prompt cytoreductive chemotherapy is essential, treatment with leukapheresis is controversial. This study investigated the outcomes of patients with hyperleukocytosis who received leukapheresis. From 5596 encounters of patients with leukemia seen at Houston Methodist Hospital, we identified 26 patients who had newly diagnosed AML, WBC >50,000/μL, and received leukapheresis. We matched 26 patients who had similar baseline characteristics but did not receive leukapheresis. The primary endpoint was to compare the 28-day mortality rates between the treatment and the control groups. Secondary endpoints were 6-month, 1-year, and 2-year mortality rates. Using multivariate logistic regression analysis, leukapheresis was associated with significantly lower 28-day mortality rate (30.8% vs. 57.7%, p = .022). There was, however, no difference in long-term mortality rate. Our study demonstrates the short-term mortality benefit of using leukapheresis in AML patients presenting with hyperleukocytosis.

The utility of therapeutic plasma exchange for amphotericin B overdose

Medication error is a preventable cause of morbidity and death in the inpatient population. We describe a patient with an antifungal overdose treated with therapeutic plasma exchange (TPE). The patient was diagnosed with cryptococcal meningitis and received an acute overdose of amphotericin B deoxycholate instead of the prescribed liposomal amphotericin B. Consequently, the patient developed clinical symptoms including tremors, hypertension, visual hallucinations, vertigo, fever, and acute renal failure. A series of four TPEs was emergently initiated, resulting in complete resolution of most symptoms.

Ultrasound view of vein collapse during therapeutic apheresis performed with peripheral access: THERAPEUTIC APHERESIS VEIN COLLAPSE

Therapeutic apheresis requires adequate vascular access to achieve inlet flow rates of approximately 50 to 100 mL/min. While dialysis-type central venous catheters can usually provide such access, their use includes several associated risks. Some of these risks can be mitigated if peripheral venous access can be established. We have found that ultrasound guidance is helpful in establishing and maintaining such access. Inadequate peripheral vascular access often results in “low inlet pressure” (LIP) alarms on the apheresis machine. Prior to the use of ultrasound, efforts to investigate and correct LIP alarms often resulted in “blind” repositioning of the access needle. This approach can increase the risk of patient or donor injury. The clip demonstrates what we have found is a common cause of LIP alarms: vein collapse at the tip of the access needle. Video Clip S1 was taken during the investigation of repeated LIP alarms in two outpatients undergoing therapeutic plasma exchange (TPE) for myasthenia gravis at a rate of 50 mL/min, the slowest recommended rate. The clip demonstrates that even at that slow rate, the access vein would collapse under the negative pressure created by the apheresis machine. Animations are included to provide visualization of the collapse associated with pump start/stop and alarms. REPRESENTATIVE STATIONARY PICTURE. [Color figure can be viewed at wileyonlinelibrary.com]

An extremely rare splice site mutation in the gene encoding complement factor I in a patient with atypical hemolytic uremic syndrome

Atypical hemolytic uremic syndrome (aHUS) is a rare disease characterized by thrombocytopenia, microangiopathic hemolytic anemia, and acute kidney failure. The disease is difficult to diagnose due to its similarity with other hematologic disorders, such as thrombotic thrombocytopenic purpura (TTP). However, genetic mutations are found in 50–70% of patients with aHUS and can be useful in its diagnosis.