Hyperfibrinolysis Is an Important Cause of Early Hemorrhage in Patients with Acute Promyelocytic Leukemia

Biochemical risk factors and outcomes of acute promyelocytic leukemia patients with thrombotic events: a matched pair analysis

Acute promyelocytic leukemia (APL) stands out as a distinctive form of acute leukemia, exhibiting a higher occurrence of thrombotic events when contrasted with other leukemia subtypes. Since thrombosis is a relatively rare but unfavorable condition with poor prognostic implications, it is crucial to determine the risk factors for thrombotic events in APL(thrombosis in large venous or arterial from onset to differentiation therapy in 30d). We performed a retrospective study involving 950 APL patients between January 2000 and October 2022, from which 123 were excluded by younger than 16 years of age, 95 were excluded by incomplete data, and 6 were excluded by thrombosis related to CVC or PICC. A total of 23 APL patients with thrombosis for inclusion in our analysis were performed a 1:5 ratio matching based on sex (perfect match) and age (within 5 years) to patients without thrombosis. These patients were continuously monitored in the outpatient department over a period of 5 years. We meticulously examined clinical and laboratory data to pinpoint the risk factors related to thrombotic events in APL. Our primary clinical endpoints were all-cause mortality and achieving complete remission, while secondary clinical outcomes included APL relapse. Thrombotic events were observed in 2.4% (23/950) of APL patients. Compared to patients without thrombosis, patients with thrombosis had higher lactate dehydrogenase (LDH) [313 (223, 486) vs. 233 (188, 367) U/L, p = 0.020], higher indirect bilirubin [11.2 (7.4, 18.6) vs.8.3 (6.0, 10.7) umol/L, p = 0.004], higher creatinine [72 (62, 85) vs. 63 (54, 74) umol/L, p = 0.026], higher CD2 expression (65.2 vs. 15.2%, p < 0.001), higher CD15 expression (60.9 vs. 24.3%, p = 0.001), and PML/RARαisoforms (p < 0.001). Multivariate-logistic-regression analysis revealed several factors that were markedly related to thrombosis, including LDH (OR≈1.003, CIs≈1.000-1.006, p = 0.021), indirect bilirubin (OR≈1.084, CIs≈1.000-1.188, p = 0.043), CD2 expression positive (OR≈16.629, CIs≈4.001-62.832, p < 0.001), and CD15 expression positive (OR≈7.747, CIs≈2.005-29.941, p = 0.003). The S-type (OR≈0.012, CIs≈0.000-0.310, p = 0.008) and L-type (OR≈0.033, CIs≈0.002-0.609, p = 0.022) PML/RARα isoforms were negatively associated with thrombosis. Kaplan-Meier curves indicated that the survival rates were remarkably varied between APL patients with and without thrombosis (HR:21.34, p < 0.001). LDH and indirect bilirubin are variables significantly associated with thrombosis in APL, S-type and L-type PML/RARαisoforms exhibit a negative association with thrombotic events. The thrombotic events of APL can predict the subsequent survival of thrombosis. The findings of our study have the potential to facilitate early detection of thrombosis and enhance the prognosis for individuals with APL who develop thrombosis. Further validation of our findings will be essential through future prospective or multicenter studies.

Early mortality continues to be a barrier to excellent survival in childhood acute promyelocytic leukemia: a retrospective study of 62 patients spanning 17 years

Data on childhood acute promyelocytic leukemia (APL) from low-and middle-income countries is limited. Early mortality is a concern and often not highlighted in clinical trials. The retrospective study was conducted on patients (≤12 years) with APL from 2003 to 2021 at a single center in India. Patients were treated with all-trans-retinoic acid (ATRA) and chemotherapy. Induction and three courses of consolidation were followed by maintenance for 2 years. In 2015, the protocol was updated with following modifications: (a) obtaining diagnostic cerebrospinal fluid at end-of-induction rather than at diagnosis, (b) administering intrathecal cytarabine regardless of risk-category, (c) risk-stratified administration of chemotherapy, and (d) inclusion of ATRA in all the cycles of consolidation. Sixty-two patients were diagnosed over the 17 years. The median age was 8 years (range: 0.9-12). Half had high-risk disease. Differentiation syndrome was observed in 32%, none being fatal. Eighteen (29%) patients died due to hemorrhage (83%) or septicemia (17%). Thirteen (21%) had early mortality (≤15 days), all due to hemorrhage. A platelet count <20 × 10⁹/L predicted early mortality (odds ratio: 4.5; 95% CI: 0.9-22, p = 0.06). Treatment abandonment reduced from 23.5% during 2003-2015 to nil during 2015-2021 (p = 0.006). Three (8%) patients relapsed. The 4-year OS of all patients and the patients who survived >15 days was 70.1% and 89.6%, respectively. The 4-year EFS, including abandonment and early mortality, before and following updated protocol, was 61.4% and 65.5%, respectively (p = 0.77). Early mortality continues to be a barrier to an otherwise excellent survival in childhood APL. A significant reduction in treatment abandonment in recent years is gratifying.

Prevalence and outcomes of thrombotic and hemorrhagic complications in pediatric acute promyelocytic leukemia in a tertiary Brazilian center

INTRODUCTION

Little attention is given to thrombosis associated with pediatric acute promyelocytic leukemia (APL). This study describes the thrombotic and hemorrhagic manifestations of APL in pediatric patients and evaluates their hemostasis, based on coagulation tests.

METHODS

Inclusion criteria were age 0-18 years and APL diagnosis between April 2005 and November 2017. Patients who had received blood transfusion prior to coagulation tests were excluded. Baseline coagulation tests, hematologic counts, and hemorrhagic/thrombotic manifestations were evaluated.

RESULTS

Median age was 10.7 years (1-15 years). The initial coagulation tests revealed a median Hgb of 8.3 g/dL (4.7-12.9 g/dL), median leucocyte count of 10.9 × 10⁹/L (1.1-95.8 × 10⁹/L), median platelet count of 31.8 × 10⁹/L (2.0-109.0 × 10⁹/L), median activated partial thromboplastin time (aPTT) of 31.7 s (23.0-50.4 s), median aPTT ratio of 1.0 (0.78-1.6), median thromboplastin time (PT) of 17.5 s (13.8-27.7 s), median PT activity of 62% (25-95 %), and median fibrinogen of 157.7 mg/dL (60.0-281.0 mg/dL). Three patients (13%) had thrombosis. At diagnosis, 21 patients (91.3%) had bruising, one patient (4.3%) had splenic vein and artery thrombosis and one patient (4.3%) presented without thrombohemorrhagic manifestations. During treatment, two patients (8.6%) had thrombosis.

CONCLUSION

Knowledge of thrombosis in pediatric APL is important to determine its risk factors and the best way to treat and prevent this complication.

Investigation of fibrinogen in early bleeding of patients with newly diagnosed acute promyelocytic leukemia

Early hemorrhagic death remains a major cause of treatment failure in acute promyelocytic leukemia (APL). This study investigated the role of fibrinogen concentrations in early hemorrhage and overall survival (OS) of APL patients. Laboratory and clinical data, including fibrinogen concentrations and other coagulation indexes, bleeding events, and survival data, of 198 patients newly diagnosed with APL from February 2012 to December 2017 were extracted from patient records and retrospectively investigated. Patients with moderate/severe bleeding had significantly lower median fibrinogen concentrations (p = .023), higher Chinese disseminated intravascular coagulation scoring system (CDSS) (p < .001), and were more often female (p = .034) than patients with no such bleeding. Additionally, patients with fibrinogen <1.0 g/L and 1.0-1.6 g/L had significantly higher moderate/severe bleeding rates than those with fibrinogen >1.6 g/L (p = .015; p = .023). However, moderate/severe (p = .088) and severe bleeding rates (p = .063) were comparable for patients with fibrinogen <1.0 g/L and 1.0-1.6 g/L. Multivariate analysis showed that fibrinogen ≤1.6 g/L (p = .036), platelet counts ≤10 × 10⁹/L (p = .037), and CDSS scores ≥5 (p = .023) were independent risk factors for moderate/severe bleeding. Survival analysis indicated that moderate/severe bleeding (p = .018), fibrinogen ≤1.6 g/L combined with prothrombin time >12.8 s (p = .005), age ≥60 years (p = .001), and CDSS ≥5 (p = .044) were independent predictors of 1-year OS. Fibrinogen ≤1.6 g/L may be an independent risk factor for early bleeding in newly treated patients with APL and is associated with a worse 1-year OS. Increasing fibrinogen to >1.6 g/L may help to prevent bleeding.

Nicotinamide Inhibits Glycolysis of HL-60 Cells by Modulating Sirtuin 1 (SIRT1)/Peroxisome Proliferator-Activated Receptor γ Coactivator 1α (PGC-1α)/Hypoxia-Inducible Factor-2α (HIF2α) Signaling Pathway

Background

Nicotinamide can affect differentiation and proliferation of leukemia cells. This research aimed to explore the regulatory effect of nicotinamide on glycolysis metabolism of leukemia cells and to clarify the associated mechanisms.

Material/Methods

HL-60 cells were treated with nicotinamide and divided into 0.1, 1, and 10 μmol/l groups. HL-60 cells without any administration were assigned as negative control (CT group). Glucolytic activity was evaluated by detecting lactic acid production, and glucose level was measured using glucose consumption assay. Apoptosis of HL-60 was examined using flow cytometry assay, when cells were cultured for 24 h. Expressions of sirtuin 1 (SIRT1), peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), and hypoxia-inducible factor-2α (HIF2α) were evaluated using a reverse transcription PCR assay and Western blotting assay, respectively.

Results

Nicotinamide remarkably decreased lactic acid production and glucose levels in leukemia cells compared with that of the CT group (p<0.05). Nicotinamide significantly induced the apoptosis of HL-60 cells compared to that of the negative control group (p<0.05). Nicotinamide significantly inhibited the SIRT1/PGC-1α/HIF2α signaling pathway mRNAs compared to that of the CT group (p<0.05). Nicotinamide remarkably reduced mitochondrial regulatory factors SIRT1/PGC-1α expression compared to that in the CT group (p<0.05). Nicotinamide obviously downregulated HIF2α compared with that of the CT group (p<0.05). Moreover, all of the above nicotinamide-induced effects, including glycolytic activity, apoptosis, and expression of SIRT1/PGC-1α/HIF2α, were changed in a dose-dependent manner.

Conclusions

Nicotinamide can inhibit glycolysis of HL-60 cells by inhibiting the mitochondrial regulatory factor SIRT1/PGC-1α and suppressing transcription factor HIF2α.