Economic Impact of Transformation to Acute Myeloid Leukemia Among Actively Managed Patients with Higher-Risk Myelodysplastic Syndromes in the United States.

INTRODUCTION: Transformation of higher-risk myelodysplastic syndromes (MDS) to acute myeloid leukemia (AML) may be associated with increased healthcare resource utilization (HCRU) and costs. To describe this economic impact, HCRU and costs were compared between US patients who experienced transformation to AML and those who did not. METHODS: Using the Optum administrative claims data, this retrospective matched cohort study identified patients (≥ 18 years old) with higher-risk MDS who initiated first-line therapy between January 1, 2008, and June 30, 2019. Patients whose disease transformed to AML were matched 1:1 to patients whose disease did not transform, based on the duration of follow-up. The follow-up period was divided into two periods: pre- (before transformation to AML) and post-AML (after transformation to AML). For patients who did not transform to AML, pre- and post-AML periods were determined using the transformation date of their matched pair. HCRU and total adjusted costs (2019 US dollars, $) were compared between patients who transformed to AML and those who did not. RESULTS: A total of 118 matched patient pairs were included in the study. The hospitalization rate was significantly higher in patients who transformed than in those who did not during the entire follow-up (58.8% vs. 44.1%; P = 0.0295) and post-AML (47.5% vs. 28.0%; P = 0.0028) periods. Across all periods, supportive care use was significantly higher among patients who transformed to AML vs. patients who did not transform. Adjusted mean monthly costs for patients with higher-risk MDS who transformed to AML were higher than those who did not transform ($25,964 vs. $19,150; P < 0.0001). The observed total cost difference was more notable in the post-AML period ($36,424 vs. $14,860; P < 0.0001). CONCLUSIONS: Patients with higher-risk MDS whose disease transformed to AML incurred significantly higher healthcare costs compared to those whose disease did not transform, highlighting the important need for treatments that prevent or delay transformation.

Clinical impact of transformation to acute myeloid leukemia in patients with higher-risk myelodysplastic syndromes.

Aim: Forty percent of patients with higher-risk myelodysplastic syndromes (HR-MDS) transform to acute myeloid leukemia (AML). Materials & methods: This retrospective study assessed the impact of HR-MDS transformation to AML on OS in a 6-month landmark analysis and the results were validated using a time-varying analysis. Results: The rate of AML transformation was 26.9% at 1 year. Patients who transformed to AML had a higher risk of death than patients who did not in the 6-month landmark analysis (HR: 1.82; p: 0.0072) and time-varying analysis at 1 year (HR: 2.85; p < 0.0001). Patients treated with azacitidine and decitabine in first-line therapy had similar results. Conclusion: HR-MDS transformation to AML is associated with inferior OS in patients with HR-MDS initiating first-line therapy.

Up to 40% of patients with higher-risk myelodysplastic syndromes (HR-MDS) could experience deterioration or progression to acute myeloid leukemia (AML), a type of blood cancer. We conducted a study to assess whether HR-MDS progression to AML had an unfavorable impact on patient life expectancy after initiating treatment for HR-MDS. Our study concluded that patients who experienced progression to AML had a higher chance of dying immediately after their progression to AML than patients who did not. Patients who received azacitidine and decitabine as their first treatment for HR-MDS had similar results.

Genome-wide identification of microRNAs regulating cholesterol and triglyceride homeostasis.

Genome-wide association studies (GWASs) have linked genes to various pathological traits. However, the potential contribution of regulatory noncoding RNAs, such as microRNAs (miRNAs), to a genetic predisposition to pathological conditions has remained unclear. We leveraged GWAS meta-analysis data from >188,000 individuals to identify 69 miRNAs in physical proximity to single-nucleotide polymorphisms (SNPs) associated with abnormal levels of circulating lipids. Several of these miRNAs (miR-128-1, miR-148a, miR-130b, and miR-301b) control the expression of key proteins involved in cholesterol-lipoprotein trafficking, such as the low-density lipoprotein (LDL) receptor (LDLR) and the ATP-binding cassette A1 (ABCA1) cholesterol transporter. Consistent with human liver expression data and genetic links to abnormal blood lipid levels, overexpression and antisense targeting of miR-128-1 or miR-148a in high-fat diet-fed C57BL/6J and Apoe-null mice resulted in altered hepatic expression of proteins involved in lipid trafficking and metabolism, and in modulated levels of circulating lipoprotein-cholesterol and triglycerides. Taken together, these findings support the notion that altered expression of miRNAs may contribute to abnormal blood lipid levels, predisposing individuals to human cardiometabolic disorders.

MicroRNA-33 and the SREBP host genes cooperate to control cholesterol homeostasis.

Proper coordination of cholesterol biosynthesis and trafficking is essential to human health. The sterol regulatory element-binding proteins (SREBPs) are key transcription regulators of genes involved in cholesterol biosynthesis and uptake. We show here that microRNAs (miR-33a/b) embedded within introns of the SREBP genes target the adenosine triphosphate-binding cassette transporter A1 (ABCA1), an important regulator of high-density lipoprotein (HDL) synthesis and reverse cholesterol transport, for posttranscriptional repression. Antisense inhibition of miR-33 in mouse and human cell lines causes up-regulation of ABCA1 expression and increased cholesterol efflux, and injection of mice on a western-type diet with locked nucleic acid-antisense oligonucleotides results in elevated plasma HDL. Our findings indicate that miR-33 acts in concert with the SREBP host genes to control cholesterol homeostasis and suggest that miR-33 may represent a therapeutic target for ameliorating cardiometabolic diseases.

Total lymphocyte deficiency attenuates AngII-induced atherosclerosis in males but not abdominal aortic aneurysms in apoE deficient mice.

OBJECTIVE: T and B lymphocytes are associated with atherosclerosis and aneurysms. Angiotensin II (AngII) infusion into hypercholesterolemic mice results in augmentation of atherosclerosis and abdominal aortic aneurysm (AAA) formation. In this study, we determined whether total lymphocyte deficiency reduced AngII-induced vascular diseases. METHODS AND RESULTS: ApoE deficient (apoE -/-) mice were cross-bred with recombination activating gene-1 (Rag-1) deficient mice that lack mature T and B lymphocytes. Heterozygous littermates (Rag-1 +/-) have normal lymphocytic function and served as controls. Male and female apoE -/- mice that were either Rag-1 +/- or -/- were fed a normal laboratory diet and infused with either saline or AngII (1000ng/kg/min) subcutaneously via osmotic mini pump for 28 days. Total lymphocyte deficiency had no significant effect on body weight and systolic blood pressure prior to and during AngII infusion. However, it was associated with decreased serum cholesterol concentrations. AngII infusion increased atherosclerotic lesion area in Rag-1 +/- mice compared to saline (P=0.017 in males and P=0.004 in females). This effect was significantly blunted in Rag-1 -/- male (P=0.044), but not female mice. AngII-infusion promoted increased width of the abdominal aorta, with a greater effect in males. Despite the reduction in atherosclerosis in males, Rag-1 deficiency had no significant effect on AngII-induced aortic dilation in either gender. CONCLUSION: T and B lymphocyte deficiency attenuates AngII-induced atherosclerosis in males but not AAA formation in apoE -/- mice.

Pharmacological inhibition of BLT1 diminishes early abdominal aneurysm formation.

Leukotriene B(4) (LTB(4)) is a pro-inflammatory lipid mediator generated by the enzymes 5-lipoxygenase (5-LO) and LTA(4)-hydrolase. LTB(4) signals primarily through its G protein-coupled receptor BLT1, which is highly expressed on specific leukocyte subsets. Recent genetic studies in humans as well as knockout studies in mice have implicated the leukotriene synthesis pathway in several vascular pathologies. Here we tested the hypothesis that pharmacological inhibition of BLT1 diminishes abdominal aortic aneurysm (AAA) formation, a major complication associated with atherosclerotic vascular disease. Chow-fed Apoe(-/-) mice were treated with a 4-week infusion of Angiotensin II (AngII, 1000 ng/(kg min)) beginning at 10 weeks of age, in a well-established murine AAA model. Administration of the selective BLT1 antagonist CP-105,696 beginning simultaneously with AngII infusion reduced the incidence of AAA formation from 82% to 40% (p<0.05). There was a concordant reduction in maximal aortic diameter from 2.35 mm to 1.56 mm (p<0.05). While administration of the antagonist on day 14 after the onset of AngII infusion diminished lesional macrophage accumulation, it did not significantly alter the size of AAA by day 42. Thus, pharmacological inhibition of BLT1 may ultimately hold clinical promise, but early intervention may be critical.

Interferon-gamma and the interferon-inducible chemokine CXCL10 protect against aneurysm formation and rupture.

BACKGROUND: Vascular disease can manifest as stenotic plaques or ectatic aneurysms, although the mechanisms culminating in these divergent disease manifestations remain poorly understood. T-helper type 1 cytokines, including interferon-gamma and CXCL10, have been strongly implicated in atherosclerotic plaque development. METHODS AND RESULTS: Here, we specifically examined their role in the formation of abdominal aortic aneurysms in the angiotensin II-induced murine model. Unexpectedly, we found increased suprarenal aortic diameters, abdominal aortic aneurysm incidence, and aneurysmal death in apolipoprotein E- and interferon-gamma-deficient (Apoe(-/-)/Ifng(-/-)) mice compared with Apoe(-/-) controls, although atherosclerotic luminal plaque formation was attenuated. The interferon-gamma-inducible T-cell chemoattractant CXCL10 was highly induced by angiotensin II infusion in Apoe(-/-) mice, but this induction was markedly attenuated in Apoe(-/-)/Ifng(-/-) mice. Apoe(-/-)/Cxcl10(-/-) mice had decreased luminal plaque but also increased aortic size, worse morphological grades of aneurysms, and a higher incidence of death due to aortic rupture than Apoe(-/-) controls. Furthermore, abdominal aortic aneurysms in Apoe(-/-)/Cxcl10(-/-) mice were enriched for non-T-helper type 1-related signals, including transforming growth factor-beta1. Treatment of Apoe(-/-)/Cxcl10(-/-) mice with anti-transforming growth factor-beta neutralizing antibody diminished angiotensin II-induced aortic dilation. CONCLUSIONS: The present study defines a novel pathway in which interferon-gamma and its effector, CXCL10, contribute to divergent pathways in abdominal aortic aneurysm versus plaque formation, inhibiting the former pathology but promoting the latter. Thus, efforts to develop antiinflammatory strategies for atherosclerosis must carefully consider potential effects on all manifestations of vascular disease.

Inhibited aortic aneurysm formation in BLT1-deficient mice.

Leukotriene B(4) is a proinflammatory lipid mediator generated by the enzymes 5-lipoxygenase and leukotriene A(4) hydrolase. Leukotriene B(4) signals primarily through its high-affinity G protein-coupled receptor, BLT1, which is highly expressed on specific leukocyte subsets. Recent genetic studies in humans as well as knockout studies in mice have implicated the leukotriene synthesis pathway in several vascular pathologies. In this study, we tested the hypothesis that BLT1 is necessary for abdominal aortic aneurysm (AAA) formation, a major complication of atherosclerotic vascular disease. Chow-fed Apoe(-/-) and Apoe(-/-)/Blt1(-/-) mice were treated with a 4-wk infusion of angiotensin II (1000 ng/min/kg) beginning at 20 wk of age, in a well-established murine AAA model. We found a reduced incidence of AAA formation as well as concordant reductions in the maximum suprarenal/infrarenal diameter and total suprarenal/infrarenal area in the angiotensin II-treated Apoe(-/-)/Blt1(-/-) mice as compared with the Apoe(-/-) controls. Diminished AAA formation in BLT1-deficient mice was associated with significant reductions in mononuclear cell chemoattractants and leukocyte accumulation in the vessel wall, as well as striking reductions in the production of matrix metalloproteinases-2 and -9. Thus, we have shown that BLT1 contributes to the frequency and size of abdominal aortic aneurysms in mice and that BLT1 deletion in turn inhibits proinflammatory circuits and enzymes that modulate vessel wall integrity. These findings extend the role of BLT1 to a critical complication of vascular disease and underscore its potential as a target for intervention in modulating multiple pathologies related to atherosclerosis.