The Anti-Tumorigenic Role of Cannabinoid Receptor 2 in Non-Melanoma Skin Cancer.

Five million non-melanoma skin cancers occur globally each year, and it is one of the most common malignant cancers. The dysregulation of the endocannabinoid system, particularly cannabinoid receptor 2 (CB2), is implicated in skin cancer development, progression, and metastasis. Comparing wildtype (WT) to systemic CB2 knockout (CB2-/-) mice, we performed a spontaneous cancer study in one-year old mice, and subsequently used the multi-stage chemical carcinogenesis model, wherein cancer is initiated by 7,12-dimethylbenz[a]anthracene (DMBA) and promoted by 12-O-tetradecanoylphorbol-13-acetate (TPA). We found that aging CB2-/- mice have an increased incidence of spontaneous cancerous and precancerous skin lesions compared to their WT counterparts. In the DMBA/TPA model, CB2-/- developed more and larger papillomas, had decreased spontaneous regression of papillomas, and displayed an altered systemic immune profile, including upregulated CD4+ T cells and dendritic cells, compared to WT mice. Immune cell infiltration in the tumor microenvironment was generally low for both genotypes, although a trend of higher myeloid-derived suppressor cells was observed in the CB2-/- mice. CB2 expression in carcinogen-exposed skin was significantly higher compared to naïve skin in WT mice, suggesting a role of CB2 on keratinocytes. Taken together, our data show that endogenous CB2 activation plays an anti-tumorigenic role in non-melanoma skin carcinogenesis, potentially via an immune-mediated response involving the alteration of T cells and myeloid cells coupled with the modulation of keratinocyte activity.

Erythropoietin Receptor (EPOR) Signaling in the Osteoclast Lineage Contributes to EPO-Induced Bone Loss in Mice.

Erythropoietin (EPO) is a pleiotropic cytokine that classically drives erythropoiesis but can also induce bone loss by decreasing bone formation and increasing resorption. Deletion of the EPO receptor (EPOR) on osteoblasts or B cells partially mitigates the skeletal effects of EPO, thereby implicating a contribution by EPOR on other cell lineages. This study was designed to define the role of monocyte EPOR in EPO-mediated bone loss, by using two mouse lines with conditional deletion of EPOR in the monocytic lineage. Low-dose EPO attenuated the reduction in bone volume (BV/TV) in Cx3cr1Cre EPORf/f female mice (27.05%) compared to controls (39.26%), but the difference was not statistically significant. To validate these findings, we increased the EPO dose in LysMCre model mice, a model more commonly used to target preosteoclasts. There was a significant reduction in both the increase in the proportion of bone marrow preosteoclasts (CD115+) observed following high-dose EPO administration and the resulting bone loss in LysMCre EPORf/f female mice (44.46% reduction in BV/TV) as compared to controls (77.28%), without interference with the erythropoietic activity. Our data suggest that EPOR in the monocytic lineage is at least partially responsible for driving the effect of EPO on bone mass.

Unraveling a Nosocomial Outbreak of COVID-19: The Role of Whole-Genome Sequence Analysis.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic poses many epidemiological challenges. The investigation of nosocomial transmission is usually performed via thorough investigation of an index case and subsequent contact tracing. Notably, this approach has a subjective component, and there is accumulating evidence that whole-genome sequencing of the virus may provide more objective insight. METHODS: We report a large nosocomial outbreak in 1 of the medicine departments in our institution. Following intensive epidemiological investigation, we discovered that 1 of the patients involved was suffering from persistent COVID-19 while initially thought to be a recovering patient. She was therefore deemed to be the most likely source of the outbreak. We then performed whole-genome sequencing of the virus of 14 infected individuals involved in the outbreak. RESULTS: Surprisingly, the results of whole-genome sequencing refuted our initial hypothesis. A phylogenetic tree of the samples showed multiple introductions of the virus into the ward, 1 of which led to a cluster of 10 of the infected individuals. Importantly, the results pointed in the direction of a specific index patient that was different from the 1 that arose from our initial investigation. CONCLUSIONS: These results underscore the important added value of using whole-genome sequencing in epidemiological investigations as it may reveal unexpected connections between cases and aid in understanding transmission dynamics, especially in the setting of a pandemic where multiple possible index cases exist simultaneously.

A predictive algorithm using clinical and laboratory parameters may assist in ruling out and in diagnosing MDS.

We present a noninvasive Web-based app to help exclude or diagnose myelodysplastic syndrome (MDS), a bone marrow (BM) disorder with cytopenias and leukemic risk, diagnosed by BM examination. A sample of 502 MDS patients from the European MDS (EUMDS) registry (n > 2600) was combined with 502 controls (all BM proven). Gradient-boosted models (GBMs) were used to predict/exclude MDS using demographic, clinical, and laboratory variables. Area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were used to evaluate the models, and performance was validated using 100 times fivefold cross-validation. Model stability was assessed by repeating its fit using different randomly chosen groups of 502 EUMDS cases. AUC was 0.96 (95% confidence interval, 0.95-0.97). MDS is predicted/excluded accurately in 86% of patients with unexplained anemia. A GBM score (range, 0-1) of less than 0.68 (GBM < 0.68) resulted in a negative predictive value of 0.94, that is, MDS was excluded. GBM ≥ 0.82 provided a positive predictive value of 0.88, that is, MDS. The diagnosis of the remaining patients (0.68 ≤ GBM < 0.82) is indeterminate. The discriminating variables: age, sex, hemoglobin, white blood cells, platelets, mean corpuscular volume, neutrophils, monocytes, glucose, and creatinine. A Web-based app was developed; physicians could use it to exclude or predict MDS noninvasively in most patients without a BM examination. Future work will add peripheral blood cytogenetics/genetics, EUMDS-based prospective validation, and prognostication.

The Non-Erythropoietic EPO Analogue Cibinetide Inhibits Osteoclastogenesis In Vitro and Increases Bone Mineral Density in Mice.

The two erythropoietin (EPO) receptor forms mediate different cellular responses to erythropoietin. While hematopoiesis is mediated via the homodimeric EPO receptor (EPOR), tissue protection is conferred via a heteromer composed of EPOR and CD131. In the skeletal system, EPO stimulates osteoclast precursors and induces bone loss. However, the underlying molecular mechanisms are still elusive. Here, we evaluated the role of the heteromeric complex in bone metabolism in vivo and in vitro by using Cibinetide (CIB), a non-erythropoietic EPO analogue that exclusively binds the heteromeric receptor. CIB is administered either alone or in combination with EPO. One month of CIB treatment significantly increased the cortical (~5.8%) and trabecular (~5.2%) bone mineral density in C57BL/6J WT female mice. Similarly, administration of CIB for five consecutive days to female mice that concurrently received EPO on days one and four, reduced the number of osteoclast progenitors, defined by flow cytometry as Lin-CD11b-Ly6Chi CD115+, by 42.8% compared to treatment with EPO alone. In addition, CIB alone or in combination with EPO inhibited osteoclastogenesis in vitro. Our findings introduce CIB either as a stand-alone treatment, or in combination with EPO, as an appealing candidate for the treatment of the bone loss that accompanies EPO treatment.

Erythropoietin Treatment Is Associated with Decreased Blood Glucose Levels in Hematologic Patients.

BACKGROUND: Erythroid stimulating agents (ESAs) have pleiotropic effects, and in animal and human studies those exposed to high erythropoietin had lower blood glucose. OBJECTIVE: To determine the association between ESA and glucose in anemia-treated patients with myelodysplastic syndromes (MDS) or multiple myeloma (MM). PATIENTS AND METHODS: Patients' glucose levels were compared while on to while off ESA, and all served as their own controls. To test the association between ESA and blood glucose, we employed a linear mixed model, accounting for variability in the number of measurements for each patient. RESULTS: Charts of 20 patients were reviewed. Mean age was 77 ± 9.8 years (range 50-91). Thirteen patients had MDS, and 8 had MM (1 with both). Glucose (mean ± standard error of the mean) was 116.38 ± 5.21 mg/dL without ESA, as opposed to 105.64 ± 5.11 mg/dL with ESA (p < 0.0001). The 3 diabetic and 5 steroid-treated patients also demonstrated reduced glucose by approximately 19 mg/dL with ESA (p = 0.003 and p = 0.0001, respectively). There was no difference in collective hemoglobin levels between the 2 groups. CONCLUSION: ESA treatment for anemia is associated with lower blood glucose in hematologic patients. In those who also have diabetes mellitus, ESA might contribute to glucose control, and even to hypoglycemia. Glucose monitoring is thus advised. Further studies with both diabetic and nondiabetic patients are needed to clarify this association and underlying mechanisms.

Anti-CD20-Mediated B Cell Depletion Is Associated With Bone Preservation in Lymphoma Patients and Bone Mass Increase in Mice.

Immunotherapy with anti-CD20-specific antibodies (rituximab), has become the standard of care for B cell lymphoproliferative disorders and many autoimmune diseases. In rheumatological patients the effect of rituximab on bone mass yielded conflicting results, while in lymphoma patients it has not yet been described. Here, we used cross-sectional X-ray imaging (CT/PET-CT) to serially assess bone density in patients with follicular lymphoma receiving rituximab maintenance therapy. Remarkably, this treatment prevented the decline in bone mass observed in the control group of patients who did not receive active maintenance therapy. In accordance with these data, anti-CD20-mediated B cell depletion in normal C57BL/6J female mice led to a significant increase in bone mass, as reflected by a 7.7% increase in bone mineral density (whole femur), and a ~5% increase in cortical as well as trabecular tissue mineral density. Administration of anti-CD20 antibodies resulted in a significant decrease in osteoclastogenic signals, including RANKL, which correlated with a reduction in osteoclastogenic potential of bone marrow cells derived from B-cell-depleted animals. Taken together, our data suggest that in addition to its anti-tumor activity, anti-CD20 treatment has a favorable effect on bone mass. Our murine studies indicate that B cell depletion has a direct effect on bone remodeling.

Erythropoietin receptor in B cells plays a role in bone remodeling in mice.

Erythropoietin (EPO) is a key regulator of erythropoiesis. However, EPO receptors (EPO-Rs) are also expressed on non-erythroid cell types, including myeloid and bone cells. Immune cells also participate in bone homeostasis. B cells produce receptor activator of nuclear factor kappa-Β ligand (RANKL) and osteoprotegerin (OPG), two pivotal regulators of bone metabolism. Here we explored the ability of B cells to transdifferentiate into functional osteoclasts and examined the role of EPO in this process in a murine model. Methods: We have combined specifically-designed experimental mouse models and in vitro based osteoclastogenesis assays, as well as PCR analysis of gene expression. Results: (i) EPO treatment in vivo increased RANKL expression in bone marrow (BM) B cells, suggesting a paracrine effect on osteoclastogenesis; (ii) B cell-derived osteoclastogenesis occured in vivo and in vitro, as demonstrated by B cell lineage tracing in murine models; (iii) B-cell-derived osteoclastogenesis in vitro was restricted to Pro-B cells expressing CD115/CSF1-R and is enhanced by EPO; (iv) EPO treatment increased the number of B-cell-derived preosteoclasts (ß3+CD115+), suggesting a physiological rationale for B cell derived osteoclastogenesis; (v) finally, mice with conditional EPO-R knockdown in the B cell lineage (cKD) displayed a higher cortical and trabecular bone mass. Moreover, cKD displayed attenuated EPO-driven trabecular bone loss, an effect that was observed despite the fact that cKD mice attained higher hemoglobin levels following EPO treatment. Conclusions: Our work highlights B cells as an important extra-erythropoietic target of EPO-EPO-R signaling and suggests their involvement in the regulation of bone homeostasis and possibly in EPO-stimulated erythropoietic response. Importantly, we present here for the first time, histological evidence for B cell-derived osteoclastogenesis in vivo.

Erythropoietin Mediated Bone Loss in Mice Is Dose-Dependent and Mostly Irreversible.

Recent studies have demonstrated that erythropoietin (EPO) treatment in mice results in trabecular bone loss. Here, we investigated the dose-response relationship between EPO, hemoglobin (Hgb) and bone loss and examined the reversibility of EPO-induced damage. Increasing doses of EPO over two weeks led to a dose-dependent increase in Hgb in young female mice, accompanied by a disproportionate decrease in trabecular bone mass measured by micro-CT (µCT). Namely, increasing EPO from 24 to 540 IU/week produced a modest 12% rise in Hgb (20.2 ± 1.3 mg/dL vs 22.7 ± 1.3 mg/dL), while trabecular bone volume fraction (BV/TV) in the distal femur decreased dramatically (27 ± 8.5% vs 53 ± 10.2% bone loss). To explore the long-term skeletal effects of EPO, we treated mice for two weeks (540 IU/week) and monitored bone mass changes after treatment cessation. Six weeks post-treatment, there was only a partial recovery of the trabecular microarchitecture in the femur and vertebra. EPO-induced bone loss is therefore dose-dependent and mostly irreversible at doses that offer only a minor advantage in the treatment of anemia. Because patients requiring EPO therapy are often prone to osteoporosis, our data advocate for using the lowest effective EPO dose for the shortest period of time to decrease thromboembolic complications and minimize the adverse skeletal outcome.

Myelodysplastic Syndromes Over Time: A Comparison of Two Patient Cohorts.

BACKGROUND: With advances in myelodysplastic syndromes (MDS), patient cohorts from different time periods might be different. OBJECTIVES: To compare presentation and outcomes between two cohorts. METHODS: Data were collected from George Washington University Medical Center, Washington, DC, USA 1986-1987 (DC), and Tel Aviv Medical Center, Israel 1999-2009 (TA). RESULTS: The study comprised 227 patients (139 TA, 88 DC). TA patients were older (75.4 ± 9.8 vs. 63.8 ± 14.3 years, P < 0.001) and had more cardiovascular diseases (56.8% vs. 14.8%, P < 0.001), fewer cytopenias (1.67 ± 0.82 vs. 2.0 ± 0.93, P = 0.003), and lower mean corpuscular volume (94.3 ± 9.9 fl vs. 100.5 ± 15.3 fl, P < 0.001). Hemoglobin, leukocyte, neutrophil, and platelet counts were similar. More TA patients had dysplasias. Bone marrow cellularity and cytogenetics were similar, but more TA patients had blasts < 5% (73.4% vs. 50.6%, P = 0.003). More TA patients had early French-American-British (FAB) disease (66.9% vs. 40.9%, P < 0.001) and lower risk disease per International Prognostic Scoring System (81% vs. 50%, P < 0.001). The 5 year survival (5YS) of TA patients was not significantly greater (62% vs. 55%). 5YS by FAB was also slightly greater for TA patients (77% vs. 65% for early FAB; 43% vs. 37% for advanced FAB, P > 0.05). CONCLUSIONS: Although patients diagnosed with MDS at a later period were older and had more cardiovascular co-morbidities, they had fewer cytopenias, tended to have earlier disease, and had minimally greater, but not significant, 5YS.

Prospective evaluation of patients hospitalized with venous thromboembolism: comparison between cancer and non-cancer patients.

BACKGROUND: Little is known about the epidemiology of venous thromboembolism in hospitalized patients in Israel. Also, a direct comparison of the clinical and laboratory features between cancer and non-cancer patients has not yet been reported. OBJECTIVES: To investigate and compare the epidemiologic, clinical and laboratory characteristics of cancer and non-cancer patients hospitalized with venous thromboembolism in a large referral medical center in Israel. METHODS: Between February 2002 and February 2003, patients diagnosed at the Rambam Medical Center as suffering from VTE (deep vein thrombosis and/or pulmonary embolism), based on diagnostic findings on Doppler ultrasonography, spiral computed tomography scan or lung scan showing high probability for pulmonary embolism, were prospectively identified and evaluated. In addition, at the conclusion of the study period, the reports of spiral chest CT scans, performed during the aforementioned period in this hospital, were retrospectively reviewed to minimize the number of unidentified cases. Blood samples were drawn for evaluation of the coagulation profile. RESULTS: Altogether, 147 patients were identified and 153 VTE events diagnosed, accounting for 0.25% of all hospitalizations during the study period. The cancer group included 63 patients (43%), most of whom had advanced disease (63%). The most common malignancies were cancer of the lung (16%), breast (14%), colon (11%) and pancreas (10%). Of 122 DVT events (with or without pulmonary embolism) there were 14 upper extremity thromboses (12%). The most common risk factors for VTE, except malignancy, were immobilization (33%), surgery/trauma (20%) and congestive heart failure (17%). There was no difference in prevalence of various risk factors between cancer and non-cancer patients. During an acute VTE event, D-dimer levels were higher in cancer patients than non-cancer patients (4.27 +/- 4.04 vs. 2.58 +/- 1.83 mg/L respectively, P = 0.055). Relatively low values of activated protein C sensitivity ratio and normalized protein C activation time were observed in both cancer and non-cancer groups (2.05 +/- 0.23 vs. 2.01 +/- 0.33 and 0.75 +/- 0.17 vs. 0.71 +/- 0.22, respectively). These values did not differ significantly between the groups. CONCLUSION: The proportion of cancer patients among patients suffering from VTE was high. Their demographic, clinical and laboratory characteristics (during an acute event) were not different from those of non-cancer patients, except for higher D-dimer levels.