Bisphosphonates: restrictions for vasculogenesis and angiogenesis: inhibition of cell function of endothelial progenitor cells and mature endothelial cells in vitro

Abstract Bisphosphonate-associated osteonecrosis of the jaws (BP-ONJ) is one of the main side effects in patients treated with bisphosphonates for metastasis to the bone or osteoporosis. BP-ONJ usually occurs in patients treated with highly potent nitrogen-containing bisphosphonates. The exact mechanism of action and etiopathology is still unknown. In addition to inhibition of bone remodelling, an anti-angiogenetic effect has become the focus of research. The aim of these study was to investigate the effect of different bisphosphonates on human umbilicord vein endothelial cells (HUVEC) and endothelial progenitor cells (EPC), which play an important role in angiogenesis. Using varying concentrations, the impact of one non-nitrogencontaining bisphosphonate (clodronate) and three nitrogencontaining bisphosphonates (ibandronate, pamidronate and zoledronate) on HUVEC and EPC was analysed. The biologic behaviour of HUVEC after incubation with different bisphosphonates was measured in a Boyden migration assay as well as in a 3D angiogenesis assay. The number of apoptotic cells was measured by Tunnel assay. To underline the importance of neoangiogenesis in the context of BP-ONJ, we measured the EPC number after incubation with different bisphosphonates in vitro. HUVEC and EPC were significantly influenced by bisphosphonates at different concentrations compared with the non-treated control groups. The nitrogen-containing bisphosphonates pamidronate and zoledronate had the greatest impact on the cells, whereas clodronate followed by ibandronate was less distinct on cell function. These results underline the hypothesis that inhibited angiogenesis induced by bisphosphonates might be of relevance in the development and maintenance of BP-ONJ. The increased impact by highly potent bisphosphonates on HUVEC and EPC may explain the high prevalence of BP-ONJ in patients undergoing this treatment

Commentaire

Therapeutic resistance remains the principal problem in acute myeloid leukemia (AML). We used area under receiver-operating characteristic curves (AUCs) to quantify our ability to predict therapeutic resistance in individual patients, where AUC=1.0 denotes perfect prediction and AUC=0.5 denotes a coin flip, using data from 4601 patients with newly diagnosed AML given induction therapy with 3+7 or more intense standard regimens in UK Medical Research Council/National Cancer Research Institute, Dutch–Belgian Cooperative Trial Group for Hematology/Oncology/Swiss Group for Clinical Cancer Research, US cooperative group SWOG and MD Anderson Cancer Center studies. Age, performance status, white blood cell count, secondary disease, cytogenetic risk and FLT3-ITD/NPM1 mutation status were each independently associated with failure to achieve complete remission despite no early death (‘primary refractoriness’). However, the AUC of a bootstrap-corrected multivariable model predicting this outcome was only 0.78, indicating only fair predictive ability. Removal of FLT3-ITD and NPM1 information only slightly decreased the AUC (0.76). Prediction of resistance, defined as primary refractoriness or short relapse-free survival, was even more difficult. Our limited ability to forecast resistance based on routinely available pretreatment covariates provides a rationale for continued randomization between standard and new therapies and supports further examination of genetic and posttreatment data to optimize resistance prediction in AML

NKX2-3 Transcriptional Regulation of Endothelin-1 and VEGF Signaling in Human Intestinal Microvascular Endothelial Cells

BACKGROUND: NKX2-3 is associated with inflammatory bowel disease (IBD). NKX2-3 is expressed in microvascular endothelial cells and the muscularis mucosa of the gastrointestinal tract. Human intestinal microvascular endothelial cells (HIMECs) are actively involved in the pathogenesis of IBD and IBD-associated microvascular dysfunction. To understand the cellular function of NKX2-3 and its potential role underlying IBD pathogenesis, we investigated the genes regulated by NKX2-3 in HIMEC using cDNA microarray. METHODOLOGY/PRINCIPAL FINDINGS: NKX2-3 expression was suppressed by shRNA in two HIMEC lines and gene expression was profiled by cDNA microarray. Pathway Analysis was used to identify gene networks according to biological functions and associated pathways. Validation of microarray and genes expression in intestinal tissues was assessed by RT-PCR. NKX2-3 regulated genes are involved in immune and inflammatory response, cell proliferation and growth, metabolic process, and angiogenesis. Several inflammation and angiogenesis related signaling pathways that play important roles in IBD were regulated by NKX2-3, including endothelin-1 and VEGF-PI3K/AKT-eNOS. Expression levels of NKX2-3, VEGFA, PI3K, AKT, and eNOS are increased in intestinal tissues from IBD patients and expression levels of EDN1 are decreased in intestinal tissues from IBD patients. These results demonstrated the important roles of NKX2-3, VEGF, PI3K, AKT, eNOS, and EDN1 in IBD pathogenesis. Correlation analysis showed a positive correlation between mRNA expression of NKX2-3 and VEGFA and a negative correlation between mRNA expression of NKX2-3 and EDN1 in intestinal tissues from IBD patients. CONCLUSION/RELEVANCE: NKX2-3 may play an important role in IBD pathogenesis by regulating endothelin-1 and VEGF signaling in HIMECs

AgeWell.de – study protocol of a pragmatic multi-center cluster-randomized controlled prevention trial against cognitive decline in older primary care patients

Background: In the absence of treatment options, the WHO emphasizes the identification of effective prevention strategies as a key element to counteract the dementia epidemic. Regarding the complex nature of dementia, trials simultaneously targeting multiple risk factors should be particularly effective for prevention. So far, however, only few such multi-component trials have been launched, but yielding promising results. In Germany, comparable initiatives are lacking, and translation of these complex interventions into routine care was not yet done. Therefore, AgeWell.de will be conducted as the first multi-component prevention trial in Germany which is closely linked to the primary care setting. Methods: AgeWell.de will be designed as a multi-centric, cluster-randomized controlled multi-component prevention trial. Participants will be older community-dwelling general practitioner (GP) patients (60–77 years; n = 1,152) with increased dementia risk according to CAIDE (Cardiovascular Risk Factors, Aging, and Incidence of Dementia) Dementia Risk Score. Recruitment will take place at 5 study sites across Germany. GP practices will be randomized to either intervention A (advanced) or B (basic). GPs will be blinded to their respective group assignment, as will be the statistician conducting the randomization. The multi-component intervention (A) includes nutritional counseling, physical activity, cognitive training, optimization of medication, management of vascular risk factors, social activity, and, if necessary, further specific interventions targeting grief and depression. Intervention B includes general health advice on the intervention components and GP treatment as usual. We hypothesize that over the 2-year follow-up period the intervention group A will benefit significantly from the intervention program in terms of preserved cognitive function/delayed cognitive decline (primary outcome), and other relevant (secondary) outcomes (e.g. quality of life, social activities, depressive symptomatology, cost-effectiveness). Discussion: AgeWell.de will be the first multi-component trial targeting risk of cognitive decline in older adults in Germany. Compared to previous trials, AgeWell.de covers an even broader set of interventions suggested to be beneficial for the intended outcomes. The findings will add substantial knowledge on modifiable lifestyle factors to prevent or delay cognitive decline. Trial registration: German Clinical Trials Register (reference number: DRKS00013555)

Severe Compromise of Preosteoblasts in a Surgical Mouse Model of Bisphosphonate-Associated Osteonecrosis of the Jaw.

Objectives: The effect of amino-bisphosphonates on osteoblastic lineage and its potential contribution to the pathogenesis of bisphosphonate-associated osteonecrosis of the jaw (BONJ) remain controversial. We assessed the effects of zoledronic acid (ZOL) on bone and vascular cells of the alveolar socket using a mouse model of BONJ. Material and Methods: Thirty-two mice were treated twice a week with either 100 μg/kg of ZOL or saline for 12 weeks. The first left maxillary molar was extracted at the third week. Alveolar sockets were assessed at both 3 weeks (intermediate) and 9 weeks (long-term) after molar extraction by semi-quantitative histomorphometry for empty lacunae, preosteoblasts (Osterix), osteoclasts (TRAP), and pericyte-like cells (CD146). Also, the bone microarchitecture was assessed by micro-CT. Results: Osteonecrotic-like lesions were observed in 21% of mice. Moreover, a decreased number of preosteoblasts contrasted with the increased number of osteoclasts at both time points. In addition, osteoclasts display multinucleation and detachment from the endosteal surface. Furthermore, the number of pericyte-like cells increased at the intermediate time point. The alveolar bone mass increased exclusively with long-term ZOL treatment. Conclusion: The severe imbalance between bone-forming cells and bone-resorbing cells showed in this study could contribute to the pathogenesis of BONJ

Serine-Rich Repeat Protein adhesins from Lactobacillus reuteri display strain specific glycosylation profiles

Lactobacillus reuteri is a gut symbiont inhabiting the gastrointestinal tract of numerous vertebrates. The surface-exposed Serine-Rich Repeat Protein (SRRP) is a major adhesin in Gram-positive bacteria. Using lectin and sugar nucleotide profiling of wild-type or L. reuteri isogenic mutants, MALDI-ToF-MS, LC-MS and GC-MS analyses of SRRPs, we showed that L. reuteri strains 100-23C (from rodent) and ATCC 53608 (from pig) can perform protein O-glycosylation and modify SRRP100-23 and SRRP53608 with Hex-Glc-GlcNAc and di-GlcNAc moieties, respectively. Furthermore, in vivo glycoengineering in E. coli led to glycosylation of SRRP53608 variants with α-GlcNAc and GlcNAcβ(1→6)GlcNAcα moieties. The glycosyltransferases involved in the modification of these adhesins were identified within the SecA2/Y2 accessory secretion system and their sugar nucleotide preference determined by saturation transfer difference NMR spectroscopy and differential scanning fluorimetry. Together, these findings provide novel insights into the cellular O-protein glycosylation pathways of gut commensal bacteria and potential routes for glycoengineering applications

Current findings for recurring mutations in acute myeloid leukemia

The development of acute myeloid leukemia (AML) is a multistep process that requires at least two genetic abnormalities for the development of the disease. The identification of genetic mutations in AML has greatly advanced our understanding of leukemogenesis. Recently, the use of novel technologies, such as massively parallel DNA sequencing or high-resolution single-nucleotide polymorphism arrays, has allowed the identification of several novel recurrent gene mutations in AML. The aim of this review is to summarize the current findings for the identification of these gene mutations (Dnmt, TET2, IDH1/2, NPM1, ASXL1, etc.), most of which are frequently found in cytogenetically normal AML. The cooperative interactions of these molecular aberrations and their interactions with class I/II mutations are presented. The prognostic and predictive significances of these aberrations are also reviewed