Postoperative Complications and Readmission Rates in Robotic-Assisted Versus Manual Total Knee Arthroplasty: Large, Propensity Score-Matched Patient Cohorts.

INTRODUCTION: There is a paucity of research comparing postoperative complication rates between manual total knee arthroplasty (M-TKA) and robotic-assisted total knee arthroplasty (RA-TKA). This study aims to compare 90-day postoperative complication, readmission, and emergency department rates between RA-TKA and M-TKA. METHODS: A retrospective review of a multihospital database identified patients who underwent TKA between January 2016 and May 2023. Surgeons who used the robotic-assisted surgery technique in <10% or >90% of their cases annually were excluded. This resulted in 15,999 cases (8,853 RA-TKAs; 7,146 M-TKAs) from 282 surgeons. RA-TKA and M-TKA cohorts were one-to-one matched based on patient sex, age, body mass index, hospital setting, surgeon experience, primary payer, and anesthesia type. Each cohort consisted of 7,146 patients (N = 14,292). 90-day revisits, specifically readmissions, readmissions with >23 hours of observation, and ED visit rates were compared between cohorts. Complications were classified according to the Clinical Classification Software schema and compared between cohorts. Mann-Whitney U, chi-squared, and Fisher exact tests, along with Bonferroni correction, were used to statistically compare cohorts. RESULTS: All-cause 90-day readmission rates were 2.4% for RA-TKA and 2.6% for M-TKA (P = 0.36). RA-TKA had fewer revisits (RA-TKA: 7.8%; M-TKA: 8.8%, P = 0.027) and rates of readmission with >23 hours of observation (RA-TKA: 1.4%; M-TKA: 2.0%, P = 0.003). RA-TKA had fewer hospital revisits due to joint stiffness (RA-TKA: 17 revisits; M-TKA: 42 revisits, P = 0.002) and chronic pain (RA-TKA: 1 revisit; M-TKA: 8 revisits, P = 0.039). Fewer readmissions were observed for acute injuries (lower extremity muscle/tendon strains) in the RA-TKA cohort (RA-TKA: 1; M-TKA: 9, P = 0.021). RA-TKA had fewer ED visits due to hematomas (RA-TKA: 0 visits; M-TKA: 7 visits, P = 0.016). CONCLUSION: In this retrospective matched cohort analysis, RA-TKA was associated with markedly fewer revisits and readmissions with >23 hours of observation compared with M-TKA. No differences in all-cause 90-day readmission were observed between cohorts. LEVEL OF EVIDENCE: Level III. STUDY DESIGN: Retrospective review.

Ultrasensitive plasma-based monitoring of tumor burden using machine-learning-guided signal enrichment.

In solid tumor oncology, circulating tumor DNA (ctDNA) is poised to transform care through accurate assessment of minimal residual disease (MRD) and therapeutic response monitoring. To overcome the sparsity of ctDNA fragments in low tumor fraction (TF) settings and increase MRD sensitivity, we previously leveraged genome-wide mutational integration through plasma whole-genome sequencing (WGS). Here we now introduce MRD-EDGE, a machine-learning-guided WGS ctDNA single-nucleotide variant (SNV) and copy-number variant (CNV) detection platform designed to increase signal enrichment. MRD-EDGESNV uses deep learning and a ctDNA-specific feature space to increase SNV signal-to-noise enrichment in WGS by ~300× compared to previous WGS error suppression. MRD-EDGECNV also reduces the degree of aneuploidy needed for ultrasensitive CNV detection through WGS from 1 Gb to 200 Mb, vastly expanding its applicability within solid tumors. We harness the improved performance to identify MRD following surgery in multiple cancer types, track changes in TF in response to neoadjuvant immunotherapy in lung cancer and demonstrate ctDNA shedding in precancerous colorectal adenomas. Finally, the radical signal-to-noise enrichment in MRD-EDGESNV enables plasma-only (non-tumor-informed) disease monitoring in advanced melanoma and lung cancer, yielding clinically informative TF monitoring for patients on immune-checkpoint inhibition.

Myocardial plasma cell tumor with intratumoral amyloidosis in a dog.

A 12-year-old mixed breed dog was evaluated for marked hypercalcemia that was identified during assessment for acute polydipsia and polyuria. Physical examination identified a new grade II/VI left apical systolic murmur. A mass involving the left ventricular posterior wall and left atrium was identified by echocardiography, suggesting neoplastic invasion into the myocardium. The patient was euthanized, and post-mortem cardiac evaluation identified an intramyocardial amyloid-producing plasma cell tumor. Multiple myeloma was suspected but could not be confirmed due to the limited post-mortem evaluation. This case is the first report of myocardial amyloidosis in a dog with a myeloma-related disorder (MRD). Dogs with MRD and myocardial involvement may not exhibit clinical signs that localize to the cardiovascular system; therefore, echocardiography should be considered during the staging process.

Value of Routine Troponin Measurement in Open Abdominal Aortic Aneurysm Repair.

BACKGROUND: Cardiovascular complications are a major cause of morbidity and mortality in the postoperative period after major vascular surgery. Depending on the study population, up to 25% of patients have troponin elevation after noncardiac surgery, yet many do not meet the diagnosis of myocardial infarction (MI). Although outcomes of routine troponin elevation in patients undergoing mixed major vascular surgery have been evaluated, this has not been studied exclusively in elective, open abdominal aortic aneurysm repair (oAAA), especially regarding perioperative and overall mortality. METHODS: We conducted a single-center, retrospective review of routine troponin surveillance for consecutive, oAAA from 2014 to 2019. A total of 319 patients were identified and analyzed for management patterns and interventions. The cohort was stratified into groups for comparison based on those in whom troponin was routinely checked (RC) as part of a care strategy during the study period, not routinely checked (NRC), elevated troponin (ET) >0.001 ng/mL, and not elevated. The median follow-up was 21.5 ± 23.8 months. Groups were compared on demographic data, cardiac comorbidities, 30-day and 3-year outcomes for MI and death using two-sample t-tests, Wilcoxon rank sum tests, Pearson chi-square tests, and Fisher exact tests when appropriate. RESULTS: Troponin was measured in 83.7% (267/319) of patients who underwent elective oAAA repair. Routine troponin checks were obtained in 79.9% (255/319) of patients. ET was identified in 16.5% of those with RC (42/255) and 4.7% of those with NRC (3/64). Of patients with ET, 37.8% (17/45) had a cardiology consultation, 4.4% (2/45) had a percutaneous coronary intervention (PCI), and 4.4% (2/45) had another cardiac intervention. All 4 patients undergoing PCI or other cardiac intervention had received routine troponin checks. Patients with ET were older (71.2 vs. 68.6; P = 0.04), more likely to receive intraoperative blood products (P = 0.003), had longer operative times (P = 0.011), higher length of stay (9 vs. 7 days; P < 0.01), and higher 30-day MI rate (3 vs. 0; P = 0.04). They had neither longer aortic clamp times nor worse preoperative cardiac function, and the proximal clamp position during oAAA repair did not impact troponin detection. Additionally, 3-year overall mortality was increased in patients who had ET but there was not a significant difference in 3-year mortality between groups receiving routine troponin checks versus not. CONCLUSIONS: ET, identified after elective oAAA repair, was associated with a higher risk of 30-day MI and lower overall survival. However, it was not demonstrated that routine assessment of troponin levels postoperatively leads to decreased 3-year mortality in this setting.

Effects of abdominal aortic aneurysm appropriateness dashboard on clinical practice.

OBJECTIVE: The Society for Vascular Surgery published abdominal aortic aneurysm (AAA) practice guidelines in 2003, 2009, and 2018 to improve the management and treatment of AAAs. In 2014, our vascular surgery department implemented a quarterly AAA dashboard (AAAdb) to record the perioperative outcomes and guideline compliance with a focus on intervention appropriateness and procedural follow-up, which supplemented our Vascular Quality Initiative data. From the available reported evidence and expert consensus opinions, nine additional criteria for the appropriate treatment of AAAs <5 cm in women and <5.5 cm in men were noted, when applicable. The purpose of our study was to assess the effects of AAAdb implementation on adherence to society and institutional guidelines, documentation of treatment rationale, and the quality of follow-up. METHODS: We performed a retrospective review of elective open and endovascular AAA repair at a single institution from 2010 to 2018. The AAAdb was implemented in the middle of this period in 2014. The patient demographics, aortic size, repair indication, repair type, 30-day mortality, and postoperative and 1-year follow-up imaging findings were analyzed. The primary outcome was adherence to intervention appropriateness and the follow-up guidelines. The categorical factors were summarized using frequencies and percentages and compared using the Pearson χ2 test or Fisher exact test. Continuous measures were summarized using the mean ± standard deviation and compared between study periods using two-sample t tests. RESULTS: From 2010 to 2018, 1549 patients had undergone elective AAA repair: 657 before and 892 after AAAdb implementation. No differences were found in AAA size after AAAdb (5.6 ± 1.2 cm vs 5.6 ± 1.1 cm; P = .88). However, the proportion of size-appropriate repairs increased (64.1% vs 71.3%; P = .003). The proportion of small AAA repairs with a documented rationale had increased (64.4% vs 80.5%; P < .001), with rapid disease progression cited most often. No difference was found in 30-day mortality (1.2% vs 1.5%; P = .69). Follow-up imaging after endovascular abdominal aortic aneurysm repair increased at <60 days postoperatively (76% vs 84%; P = .004) and at 1 year of follow-up (78% vs 86%; P = .0005). The proportion of patients with endoleak at <60 days postoperatively had increased in the post-AAAdb cohort (21% vs 29%; P = .012). CONCLUSIONS: The AAAdb served as a centerpiece for improving the appropriateness of care and compliance with national and institutional guidelines, including treatment of small AAAs in special circumstances. Its implementation was associated with higher quality follow-up and surveillance in a high-volume, regional aortic center. Consideration should be given to adding additional criteria to the Society for Vascular Surgery guidelines and Vascular Quality Initiative reporting.

Iridium-, Ruthenium-, and Nickel-Catalyzed C-C Couplings of Methanol, Formaldehyde, and Ethanol with π-Unsaturated Pronucleophiles via Hydrogen Transfer.

In this Perspective, the use of methanol and ethanol as C1 and C2 feedstocks in metal-catalyzed C-C couplings to π-unsaturated pronucleophiles via hydrogen auto-transfer is surveyed. In these processes, alcohol oxidation to form an aldehyde electrophile is balanced by reduction of an π-unsaturated hydrocarbon to form a transient organometallic nucleophile. Mechanistically related reductive couplings of paraformaldehyde mediated by alcohol reductants or formic acid also are described. These processes encompass the first catalytic enantioselective C-C couplings of methanol and ethanol and, more broadly, illustrate how the native reducing ability of alcohols enable the departure from premetalated reagents in carbonyl addition.

Disparities in Access to Radiation Therapy by Race and Ethnicity in the United States With Focus on American Indian/Alaska Native People.

OBJECTIVES: Striking disparities in access to radiation therapy (RT) exist, especially among racial and ethnic-minority patients. We analyzed census block group data to evaluate differences in travel distance to RT as a function of race and ethnicity, socioeconomic status, and rurality. METHODS: The Directory of Radiotherapy Centers provided the addresses of facilities containing linear accelerators for RT. We classified block groups as majority (≥ 50%) American Indian/Alaska Native (AI/AN), black, white, Asian, no single racial majority, or Hispanic regardless of race. We used the Area Deprivation Index to classify deprivation and Rural-Urban Commuting Area codes to classify rurality. Generalized linear mixed models tested associations between these factors and distance to nearest RT facility. RESULTS: Median distance to nearest RT facility was 72 miles in AI/AN-majority block groups, but 4 to 7 miles in block groups with non-AI/AN majorities. Multivariable models estimated that travel distances in AI/AN-majority block groups were 39 to 41 miles longer than in areas with non-AI/AN majorities. Travel distance was 1.3 miles longer in the more deprived areas versus less deprived areas and 16 to 32 miles longer in micropolitan, small town, and rural areas versus metropolitan areas. CONCLUSIONS: Cancer patients in block groups with AI/AN-majority populations, nonmetropolitan location, and low socioeconomic status experience substantial travel disparities in access to RT. Future research with more granular community- and individual-level data should explore the many other known barriers to access to cancer care and their relationship to the barriers posed by distance to RT care.

Outcomes of Gore iliac branch endoprosthesis with internal iliac component versus Gore Viabahn VBX.

OBJECTIVE: The Gore Excluder iliac branch endoprosthesis (IBE; W.L. Gore & Associates, Flagstaff, AZ) is the only iliac branch device approved in the United States to preserve blood flow to the external and internal iliac arteries (IIAs). Some surgeons have used the Gore Viabahn VBX balloon expandable endoprosthesis (VBX; W.L. Gore & Associates) in the IIA rather than the self-expanding endograft designed for the IBE, the internal iliac component (IIC). The objective of the present study was to examine the outcomes for patients treated for aortoiliac artery aneurysms using the IBE with either the IIC or VBX stent. METHODS: We performed a retrospective, single-center review of patients treated for aortoiliac artery aneurysms using the Gore IBE device, with either the IIC or VBX stent into the IIA, from February 2016 to March 2021. The patient demographics, procedure details, 30-day morbidity and mortality, and 6-month and 1-year outcomes and mortality were analyzed. The categorical factors are summarized using frequencies and proportions. Continuous measures are summarized as the mean ± standard deviation. A significance level of P = .05 was assumed for all test results. The analyses were performed using SAS software, version 9.4 (SAS Institute, Cary, NC). RESULTS: A total of 62 patients (64 arteries) had undergone elective aortoiliac artery aneurysm repair with the IBE. The IIC was used exclusively in 35 cases (55%) and the VBX in 29 (45%). The patients who had received the VBX had had a higher American Society of Anesthesiologists class (P = .006). Upper extremity access was used for VBX delivery in 24.1% of the procedures. No return to the operating room was required in either group. No differences were found in technical success (IIC, 97.1%; VBX, 93.1%; P = .59), the presence of endoleak on completion (20.0% vs 6.9%; P = .17), readmission (97.1% vs 93.1%; P = .59), or mortality (1.6% vs 0%; P = .45) at 30 days. No differences were found in the requirement for any IBE reintervention after 30 days. No type Ia, Ib, or III endoleaks had occurred in either group at any follow-up point. No significant difference was found in internal iliac limb primary patency (IIC, 100%; VBX, 96.3%) between groups. A nonstatistically significant trend was found toward fewer trunk-ipsilateral leg type II endoleaks in the VBX group during follow-up. CONCLUSIONS: These data suggest that the VBX is a reasonable substitute for the IIC, with a comparable safety and efficacy profile. Given its inherent conformability, greater range of diameters, and longer working length, the VBX stent offers expanded IIA branch options with the IBE.

Enantioselective Iridium-Catalyzed Reductive Coupling of Dienes with Oxetanones and N-Acyl-Azetidinones Mediated by 2-Propanol.

Cyclometallated iridium-PhanePhos complexes generated in situ from [Ir(cod)Cl]2 and (R)-PhanePhos catalyze 2-propanol-mediated reductive couplings of 2-substituted dienes with oxetanone and N-acyl-azetidinones to form branched homoallylic oxetanols and azetidinols with excellent control of regio- and enantioselectivity without C-C cleavage of the strained ring via enantiotopic π-facial selection of transient allyliridium nucleophiles. This work represents the first systematic study of enantioselective additions to symmetric ketones.

Genome-wide cell-free DNA mutational integration enables ultra-sensitive cancer monitoring.

In many areas of oncology, we lack sensitive tools to track low-burden disease. Although cell-free DNA (cfDNA) shows promise in detecting cancer mutations, we found that the combination of low tumor fraction (TF) and limited number of DNA fragments restricts low-disease-burden monitoring through the prevailing deep targeted sequencing paradigm. We reasoned that breadth may supplant depth of sequencing to overcome the barrier of cfDNA abundance. Whole-genome sequencing (WGS) of cfDNA allowed ultra-sensitive detection, capitalizing on the cumulative signal of thousands of somatic mutations observed in solid malignancies, with TF detection sensitivity as low as 10-5. The WGS approach enabled dynamic tumor burden tracking and postoperative residual disease detection, associated with adverse outcome. Thus, we present an orthogonal framework for cfDNA cancer monitoring via genome-wide mutational integration, enabling ultra-sensitive detection, overcoming the limitation of cfDNA abundance and empowering treatment optimization in low-disease-burden oncology care.

100th Anniversary of Macromolecular Science Viewpoint: The Past, Present, and Future of Stereocontrolled Vinyl Polymerization.

The thermomechanical properties exhibited by synthetic macromolecules can be directly linked to their tacticity, or the relative stereochemistry of repeat units. The development of stereoselective coordination-insertion polymerization, for example, led to the discovery of isotactic polypropylene, now one of the most widely produced commodity plastics in the world. Widespread interest in controlling polymer tacticity has led to a variety of stereoselective polymerization methodologies; however, this area of polymer science has lagged behind when compared to the ability to control molecular weight, dispersity, and composition. Despite decades of advancements, many stereoregular vinyl polymers remain unknown, particularly those comprised of polar functionality or derived from renewable resources. This Viewpoint provides an overview of recent developments in stereocontrolled polymerization, with an emphasis on propagation mechanism, and highlights successes, limitations, and future challenges for continued innovation.

Inversion of Enantioselectivity in Allene Gas versus Allyl Acetate Reductive Aldehyde Allylation Guided by Metal-Centered Stereogenicity: An Experimental and Computational Study.

The use of gaseous allene as an allyl pronucleophile in enantioselective aldehyde reductive coupling is described. Notably, using the same antipode of chiral ligand, (S)-tol-BINAP, an inversion of enantioselectivity is observed for allene vs allyl acetate pronucleophiles. Experimental and computational studies corroborate intervention of diastereomeric π-allyliridium-C,O-benzoate complexes, which arise via allene hydrometalation (from a pentacoordinate iridium hydride) vs allyl acetate ionization (from a square planar iridium species).

Convection enhanced delivery of panobinostat (LBH589)-loaded pluronic nano-micelles prolongs survival in the F98 rat glioma model.

BACKGROUND: The pan-histone deacetylase inhibitor panobinostat is a potential therapy for malignant glioma, but it is water insoluble and does not cross the blood-brain barrier when administered systemically. In this article, we describe the in vitro and in vivo efficacy of a novel water-soluble nano-micellar formulation of panobinostat designed for administration by convection enhanced delivery (CED). MATERIALS AND METHODS: The in vitro efficacy of panobinostat-loaded nano-micelles against rat F98, human U87-MG and M059K glioma cells and against patient-derived glioma stem cells was measured using a cell viability assay. Nano-micelle distribution in rat brain was analyzed following acute CED using rhodamine-labeled nano-micelles, and toxicity was assayed using immunofluorescent microscopy and synaptophysin enzyme-linked immunosorbent assay. We compared the survival of the bioluminescent syngenic F98/Fischer344 rat glioblastoma model treated by acute CED of panobinostat-loaded nano-micelles with that of untreated and vehicle-only-treated controls. RESULTS: Nano-micellar panobinostat is cytotoxic to rat and human glioma cells in vitro in a dose-dependent manner following short-time exposure to drug. Fluorescent rhodamine-labelled nano-micelles distribute with a volume of infusion/volume of distribution (Vi/Vd) ratio of four and five respectively after administration by CED. Administration was not associated with any toxicity when compared to controls. CED of panobinostat-loaded nano-micelles was associated with significantly improved survival when compared to controls (n=8 per group; log-rank test, P<0.001). One hundred percent of treated animals survived the 60-day experimental period and had tumour response on post-mortem histological examination. CONCLUSION: CED of nano-micellar panobinostat represents a potential novel therapeutic option for malignant glioma and warrants translation into the clinic.

Systematic chemical and molecular profiling of MLL-rearranged infant acute lymphoblastic leukemia reveals efficacy of romidepsin.

To address the poor prognosis of mixed lineage leukemia (MLL)-rearranged infant acute lymphoblastic leukemia (iALL), we generated a panel of cell lines from primary patient samples and investigated cytotoxic responses to contemporary and novel Food and Drug Administration-approved chemotherapeutics. To characterize representation of primary disease within cell lines, molecular features were compared using RNA-sequencing and cytogenetics. High-throughput screening revealed variable efficacy of currently used drugs, however identified consistent efficacy of three novel drug classes: proteasome inhibitors, histone deacetylase inhibitors and cyclin-dependent kinase inhibitors. Gene expression of drug targets was highly reproducible comparing iALL cell lines to matched primary specimens. Histone deacetylase inhibitors, including romidepsin (ROM), enhanced the activity of a key component of iALL therapy, cytarabine (ARAC) in vitro and combined administration of ROM and ARAC to xenografted mice further reduced leukemia burden. Molecular studies showed that ROM reduces expression of cytidine deaminase, an enzyme involved in ARAC deactivation, and enhances the DNA damage-response to ARAC. In conclusion, we present a valuable resource for drug discovery, including the first systematic analysis of transcriptome reproducibility in vitro, and have identified ROM as a promising therapeutic for MLL-rearranged iALL.

Mutations in desmoglein 1 cause diverse inherited palmoplantar keratoderma phenotypes: implications for genetic screening.

The inherited palmoplantar keratodermas (PPKs) are a heterogeneous group of genodermatoses, characterized by thickening of the epidermis of the palms and soles. No classification system satisfactorily unites clinical presentation, pathology and molecular pathogenesis. There are four patterns of hyperkeratosis - striate, focal, diffuse and punctate. Mutations in the desmoglein 1 gene (DSG1), a transmembrane glycoprotein, have been reported primarily in striate, but also in focal and diffuse PPKs. We report seven unrelated pedigrees with dominantly inherited PPK owing to mutations in the DSG1 gene, with marked phenotypic variation. Genomic DNA from each family was isolated, and individual exons amplified by polymerase chain reaction. Sanger sequencing was employed to identify mutations. Mutation analysis identified novel mutations in five families (p.Tyr126Hisfs*2, p.Ser521Tyrfs*2, p.Trp3*, p.Asp591Phefs*9 and p.Met249Ilefs*6) with striate palmar involvement and varying focal or diffuse plantar disease, and the recurrent mutation c.76C>T, p.Arg26*, in two families with variable PPK patterns. We report one recurrent and five novel DSG1 mutations, causing varying patterns of PPK, highlighting the clinical heterogeneity arising from mutations in this gene.

Isolated recessive nail dysplasia caused by FZD6 mutations: report of three families and review of the literature.

Congenital abnormalities of the nail are rare conditions that are most frequently associated with congenital ectodermal syndromes involving several of the epidermal appendages including the skin, teeth, hair and nails. Isolated recessive nail dysplasia (IRND) is much rarer but has recently been recognized as a condition resulting in 20-nail dystrophy in the absence of other cutaneous or extracutaneous findings. A few case reports have identified mutations in the Frizzled 6 (FZD6) gene in families presenting with abnormal nails consistent with IRND. These reports have highlighted the role of Wnt-FZD signalling in the process of nail formation. We report three families presenting with features of IRND, in whom we identified mutations in FZD6, including one previously unreported mutation.

COSMIC: High-Resolution Cancer Genetics Using the Catalogue of Somatic Mutations in Cancer.

COSMIC (http://cancer.sanger.ac.uk) is an expert-curated database of somatic mutations in human cancer. Broad and comprehensive in scope, recent releases in 2016 describe over 4 million coding mutations across all human cancer disease types. Mutations are annotated across the entire genome, but expert curation is focused on over 400 key cancer genes. Now encompassing the majority of molecular mutation mechanisms in oncogenetics, COSMIC additionally describes 10 million non-coding mutations, 1 million copy-number aberrations, 9 million gene-expression variants, and almost 8 million differentially methylated CpGs. This information combines a consistent interpretation of the data from the major cancer genome consortia and cancer genome literature with exhaustive hand curation of over 22,000 gene-specific literature publications. This unit describes the graphical Web site in detail; alternative protocols overview other ways the entire database can be accessed, analyzed, and downloaded. © 2016 by John Wiley & Sons, Inc.

High expression of connective tissue growth factor accelerates dissemination of leukaemia.

To improve treatment of acute lymphoblastic leukaemia (ALL), a better understanding of disease development is needed to tailor new therapies. Connective tissue growth factor (CTGF/CCN2) is highly expressed in leukaemia cells from the majority of paediatric patients with B-lineage ALL (pre-B ALL). CTGF is a matricellular protein and plays a role in aggressive cancers. Here we have genetically engineered leukaemia cells to modulate CTGF expression levels. Elevated CTGF levels accelerated disease dissemination and reduced survival in NOD/SCID mice. In vitro studies showed that CTGF protein induces stromal cell proliferation, promotes adhesion of leukaemia cells to stromal cells and leads to overexpression of genes associated with cell cycle and synthesis of extracellular matrix (ECM). Corresponding data from our leukaemia xenograft models demonstrated that CTGF leads to increased proliferation of non-leukaemia cells and deposition of ECM in the bone marrow. We document for the first time a functional role of CTGF in altering disease progression in a lymphoid malignancy. The findings provide support for targeting the bone marrow microenvironment in aggressive forms of leukaemia.

The gene expression signature of anagrelide provides an insight into its mechanism of action and uncovers new regulators of megakaryopoiesis.

BACKGROUND: Anagrelide is a cytoreductive agent used to lower platelet counts in essential thrombocythemia. Although the drug has been known to selectively inhibit megakaryopoiesis for many years, the molecular mechanism accounting for this activity is still unclear. OBJECTIVES AND METHODS: To address this issue we have compared the global gene expression profiles of human hematopoietic cells treated ex-vivo with and without anagrelide while growing under megakaryocyte differentiation conditions, using high-density oligonucleotide microarrays. Gene expression data were validated by the quantitative polymerase chain reaction and mined to identify functional subsets and regulatory pathways. RESULTS: We identified 328 annotated genes differentially regulated by anagrelide, including many genes associated with platelet functions and with the control of gene transcription. Prominent among the latter was TRIB3, whose expression increased in the presence of anagrelide. Pathway analysis revealed that anagrelide up-regulated genes that are under the control of the transcription factor ATF4, a known TRIB3 inducer. Notably, immunoblot analysis demonstrated that anagrelide induced the phosphorylation of eIF2α, which is an upstream regulator of ATF4, and increased ATF4 protein levels. Furthermore, salubrinal, an inhibitor of eIF2α dephosphorylation, increased the expression of ATF4-regulated genes and blocked megakaryocyte growth. CONCLUSIONS: These findings link signaling through eIF2α/ATF4 to the anti-megakaryopoietic activity of anagrelide and identify new potential modulators of megakaryopoiesis.