Safety of the pulmonary embolism rule-out criteria rule: Findings from the Registro Informatizado de la Enfermedad TromboEmbolica venosa (RIETE) registry

BACKGROUND

The diagnostic strategy for pulmonary embolism (PE) includes a D-dimer test when PE probability is low or intermediate, but false-positive D-dimer results are frequent and can result in an unnecessary computed tomography pulmonary angiogram. The PE rule-out criteria (PERC) rule excludes PE without D-dimer testing when pretest probability is <15%. The aim of this study was to assess the safety of the PERC rule strategy in patients included in the Registro Informatizado de la Enfermedad TromboEmbolica venosa (RIETE) registry.

METHODS

This retrospective cohort study used data from the RIETE registry, an ongoing, international prospective registry of patients with objectively confirmed venous thromboembolism. The primary outcome was the failure rate of the PERC strategy, represented by the proportion of PERC-negative (PERC-N) patients with a PE included in the registry. Secondary outcomes were a comparison of the clinical characteristics, treatment strategy, and outcome of PERC-N versus PERC-positive (PERC-P) patients at 3 months.

RESULTS

From 2001 to 2021, a total of 49,793 patients with acute PE were enrolled in the RIETE registry. We included 48,903 in the final analysis after exclusion of 890 patients with an undetermined PERC status. Only 346 patients were PERC-N with a failure rate of 0.7% (95% confidence interval 0.6%-0.8%). PERC-N patients presented more frequently with chest pain but less often with dyspnea, syncope, or hypotension. They also had subsegmental or segmental PE more frequently, were more often treated with direct oral anticoagulants, and received mechanical or pharmacological thrombolysis less often. In addition, PERC-N patients had a lower incidence of recurrent deep vein thrombosis, major bleeding, and death attributed to PE during the 3-month follow-up.

CONCLUSIONS

A low failure rate of the PERC rule was observed in the RIETE registry, thus supporting its use to safely identify patients with an unlikely probability of PE.

Genetic interaction between PLK1 and downstream MCPH proteins in the control of centrosome asymmetry and cell fate during neural progenitor division

Alteration of centrosome function and dynamics results in major defects during chromosome segregation and is associated with primary autosomal microcephaly (MCPH). Despite the knowledge accumulated in the last few years, why some centrosomal defects specifically affect neural progenitors is not clear. We describe here that the centrosomal kinase PLK1 controls centrosome asymmetry and cell fate in neural progenitors during development. Gain- or loss-of-function mutations in Plk1, as well as deficiencies in the MCPH genes Cdk5rap2 (MCPH3) and Cep135 (MCPH8), lead to abnormal asymmetry in the centrosomes carrying the mother and daughter centriole in neural progenitors. However, whereas loss of MCPH proteins leads to increased centrosome asymmetry and microcephaly, deficient PLK1 activity results in reduced asymmetry and increased expansion of neural progenitors and cortical growth during mid-gestation. The combination of PLK1 and MCPH mutations results in increased microcephaly accompanied by more aggressive centrosomal and mitotic abnormalities. In addition to highlighting the delicate balance in the level and activity of centrosomal regulators, these data suggest that human PLK1, which maps to 16p12.1, may contribute to the neurodevelopmental defects associated with 16p11.2-p12.2 microdeletions and microduplications in children with developmental delay and dysmorphic features.

Haspin participates in AURKB recruitment to centromeres and contributes to chromosome congression in male mouse meiosis

Chromosome segregation requires that centromeres properly attach to spindle microtubules. This essential step regulates the accuracy of cell division and therefore must be precisely regulated. One of the main centromeric regulatory signaling pathways is the Haspin-H3T3ph-chromosomal passenger complex (CPC) cascade, which is responsible for the recruitment of the CPC to the centromeres. In mitosis, Haspin kinase phosphorylates histone H3 at threonine 3 (H3T3ph), an essential epigenetic mark that recruits the CPC, whose catalytic component is Aurora B kinase. However, the centromeric Haspin-H3T3ph-CPC pathway remains largely uncharacterized in mammalian male meiosis. We have analyzed Haspin functions by either its chemical inhibition in cultured spermatocytes using LDN-192960, or the ablation of Haspin gene in Haspin-/-. Our studies suggest that Haspin kinase activity is required for proper chromosome congression during both meiotic divisions and for the recruitment of Aurora B and kinesin MCAK to meiotic centromeres. However, the absence of H3T3ph histone mark does not alter Borealin and SGO2 centromeric localization. These results add new and relevant information regarding the regulation of the Haspin-H3T3ph-CPC pathway and centromere function during meiosis.

Deficient adaptation to centrosome duplication defects in neural progenitors causes microcephaly and subcortical heterotopias

Congenital microcephaly (MCPH) is a neurodevelopmental disease associated with mutations in genes encoding proteins involved in centrosomal and chromosomal dynamics during mitosis. Detailed MCPH pathogenesis at the cellular level is still elusive, given the diversity of MCPH genes and lack of comparative in vivo studies. By generating a series of CRISPR/Cas9-mediated genetic KOs, we report here that — whereas defects in spindle pole proteins (ASPM, MCPH5) result in mild MCPH during development — lack of centrosome (CDK5RAP2, MCPH3) or centriole (CEP135, MCPH8) regulators induces delayed chromosome segregation and chromosomal instability in neural progenitors (NPs). Our mouse model of MCPH8 suggests that loss of CEP135 results in centriole duplication defects, TP53 activation, and cell death of NPs. Trp53 ablation in a Cep135-deficient background prevents cell death but not MCPH, and it leads to subcortical heterotopias, a malformation seen in MCPH8 patients. These results suggest that MCPH in some MCPH patients can arise from the lack of adaptation to centriole defects in NPs and may lead to architectural defects if chromosomally unstable cells are not eliminated during brain development.

Expanding the Differentiation Potential of Already-Established Pluripotent Stem Cells

Pluripotent stem cells (PSCs) have proven to be an essential tool in many research fields including basic cell biology, development, or human disease. In addition, we are only starting to see their potential in regenerative medicine. Manipulation and culture of PSCs, however, imposes limitations in the quality of these cells and their ability to differentiate into functional cells with physiological function. Here we propose a novel and simple technique based on the transient expression of a single microRNA molecule to expand the differentiation potency of a wide range of PSCs including induced PSCs (iPSCs) as well as embryonic stem cells (ESCs). This method requires no genetic modification of PSCs and achieves stable improvement of the differentiation potential of these cells through several cell passages both in vitro and in vivo.

Midkine signaling maintains the self-renewal and tumorigenic capacity of glioma initiating cells

Glioblastoma (GBM) is one of the most aggressive forms of cancer. It has been proposed that the presence within these tumors of a population of cells with stem-like features termed Glioma Initiating Cells (GICs) is responsible for the relapses that take place in the patients with this disease. Targeting this cell population is therefore an issue of great therapeutic interest in neuro-oncology. We had previously found that the neurotrophic factor MIDKINE (MDK) promotes resistance to glioma cell death. The main objective of this work is therefore investigating the role of MDK in the regulation of GICs.

Methods: Assays of gene and protein expression, self-renewal capacity, autophagy and apoptosis in cultures of GICs derived from GBM samples subjected to different treatments. Analysis of the growth of GICs-derived xenografts generated in mice upon blockade of the MDK and its receptor the ALK receptor tyrosine kinase (ALK) upon exposure to different treatments.

Results: Genetic or pharmacological inhibition of MDK or ALK decreases the self-renewal and tumorigenic capacity of GICs via the autophagic degradation of the transcription factor SOX9. Blockade of the MDK/ALK axis in combination with temozolomide depletes the population of GICs in vitro and has a potent anticancer activity in xenografts derived from GICs.

Conclusions: The MDK/ALK axis regulates the self-renewal capacity of GICs by controlling the autophagic degradation of the transcription factor SOX9. Inhibition of the MDK/ALK axis may be a therapeutic strategy to target GICs in GBM patients.

Thirty-day outcomes in patients with proximal deep vein thrombosis who discontinued anticoagulant therapy prematurely

INTRODUCTION

In patients receiving anticoagulation for deep vein thrombosis (DVT), a variety of reasons (including active bleeding or high-risk for bleeding) may lead into premature discontinuation of therapy (prior to completing 90 days). The relative frequency and clinical consequences of premature discontinuation in contemporary patients remain unknown.

METHODS

We used the data from RIETE, an international registry of patients with venous thromboembolism (VTE), to identify patients with proximal (above knee) lower limb DVT who prematurely discontinued anticoagulation. We assessed the incidence of the composite outcome: pulmonary embolism (PE)-related death, sudden death, or recurrent VTE within the subsequent 30 days after discontinuation and compared the risk of these events vs. the risk in patients without premature discontinuation, once adjusted for demographics and clinical factors.

RESULTS

Of 26,335 patients with proximal DVT recruited from 2001 to 2018, 1322 (5.02%) prematurely discontinued anticoagulation. Thirty days after discontinuation, 12 (0.91%) patients suffered fatal PE (n = 8) or sudden death (n = 4) and 33 (2.50%) had non-fatal recurrent VTE (PE = 15; recurrent DVT = 18). In patients with premature discontinuation, the 30-day incidence of the composite outcome was 1.62 per 1000 patient-days (95%CI: 0.00-3.80). During the first week after discontinuation, the incidence rate was 4.09 per 1000 patient-days (95%CI: 0.65-7.52). The adjusted odds of the composite outcome was 7.88 times (95%CI: 6.39-9.72) higher in patients who discontinued prematurely than in those without premature discontinuation.

CONCLUSION

Premature discontinuation of anticoagulation occurred in 5% of patients with proximal DVT, and was associated an 8-fold increased odds for the composite outcome.

Sex Differences in Patients With Occult Cancer After Venous Thromboembolism

In patients with venous thromboembolism (VTE), male sex has been associated with an increased risk of occult cancer. The influence of sex on clinical characteristics, treatment, cancer sites, and outcome has not been thoroughly investigated yet. We used the Registro Informatizado Enfermedad TromboEmbólica registry to compare the clinical characteristics, treatment strategies, cancer sites, and clinical outcomes in patients with VTE having occult cancer, according to sex. As of June 2014, 5864 patients were recruited, of whom 444 (7.6%; 95% confidence interval: 6.8-8.2) had occult cancer. Of these, 246 (55%) were men. Median time elapsed from VTE to occult cancer was 4 months (interquartile range: 2-8.4), with no sex differences. Women were older, weighed less, and were less likely to have chronic lung disease than men. The most common cancer sites were the lung (n = 63), prostate (n = 42), and colorectal (n = 29) in men and colorectal (n = 38), breast (n = 23), uterine (n = 18), hematologic (n = 17), or pancreas (n = 15) in women. Men were more likely to have lung cancer than women (2.18% vs 0.30%; P < .01) and less likely to have pancreatic cancer (0.17% vs 0.5%; P = .03). Interestingly, breast cancer was more likely found in women aged ≥50 years than in those aged <50 years (0.97% vs 0.14%; P = .03). This study highlights the existence of sex differences in patients with VTE having occult cancer. One in every 2 men had lung, prostate, or colorectal cancer. In women, there is a heterogeneity of cancer sites, increasing risk of breast cancer in those aged >50 years.

Dihydroceramide accumulation mediates cytotoxic autophagy of cancer cells via autolysosome destabilization

Autophagy is considered primarily a cell survival process, although it can also lead to cell death. However, the factors that dictate the shift between these 2 opposite outcomes remain largely unknown. In this work, we used Δ⁹-tetrahydrocannabinol (THC, the main active component of marijuana, a compound that triggers autophagy-mediated cancer cell death) and nutrient deprivation (an autophagic stimulus that triggers cytoprotective autophagy) to investigate the precise molecular mechanisms responsible for the activation of cytotoxic autophagy in cancer cells. By using a wide array of experimental approaches we show that THC (but not nutrient deprivation) increases the dihydroceramide:ceramide ratio in the endoplasmic reticulum of glioma cells, and this alteration is directed to autophagosomes and autolysosomes to promote lysosomal membrane permeabilization, cathepsin release and the subsequent activation of apoptotic cell death. These findings pave the way to clarify the regulatory mechanisms that determine the selective activation of autophagy-mediated cancer cell death.

Differential distribution of antibodies to different viruses in young animals in the free-ranging rhesus macaques of Cayo Santiago

BACKGROUND

The breeding colony of free-ranging rhesus macaques was established in 1938 in Cayo Santiago (CS) with animals collected in northern India. The seroprevalence to cercopithecine herpesvirus type 1 (B virus) and simian retroviruses has been studied previously.

RESULTS

This is the first report on the seropositivity to different viruses using samples collected shortly after removing animals (n = 245) from CS. All samples were negative for measles, simian immunodeficiency virus and simian type D retroviruses. The overall prevalence of antibodies was around 50% for simian T-lymphotropic virus I (STLV-I). For B virus, the prevalence was 38%.

CONCLUSIONS

Data obtained showed marked differences in the antibody distribution to B virus and STLV-I within the free-ranging colony of rhesus macaques. Implication of these data for the Specific Pathogen Free program at the Caribbean Primate Research Center are also discussed.

The ecology of the introduced patas monkey (Erythrocebus patas) population of southwestern Puerto Rico

This paper presents the results of a study on the introduced, free-ranging patas monkey population of Southwestern Puerto Rico (SWPR). It describes information on the population size, social group composition, diet, daily ranging patterns, and patas home range during a 3 year period. The patas monkey population in the study area consisted of approximately 120 individuals in four heterosexual groups and several all-male bands. Within their home ranges (26.8 km2), the population density was 4.47 individuals/km2. Home range size among the population's four heterosexual groups varied from 3.72 km2 to 15.39 km2, and minimum daily distance traveled ranged from 0.8-2.0 km. In general, the social structure and mating system of this population parallels what has been described for African populations. However, habitat use, ranging behavior, and the quality of intergroup interactions suggests that patas of this population exhibit territorial behavior.