ASSOCIATION OF CALCIFEDIOL LEVELS WITH VERTEBRAL FRACTURES, VASCULAR CALCIFICATIONS AND MORTALITY.

The best biomarker of Vitamin D status is calcifediol [25(OH)D]. We investigated the relationship between serum calcifediol levels and vertebral fractures (VF), vascular calcifications (VC) and mortality in hemodialysis patients. Within a multicenter, cross-sectional study in 18 hospital based dialysis centers in Italy, we included 387 hemodialysis patients (143 F, 37% ; 244 M, 63%), mean age 64±14 (SD) years, median dialytic age 49 months, BMI 25± 4 Kg/m2. We determined total 25(OH)D using the LIASON® 25 OH Vitamin D kit (DiaSorin Inc., Stillwater MN, USA). We evaluated VF with a computerized analysis of scanned L-L vertebral X-rays (T4 to L5). Reduction of > 20% of vertebral body height was considered a VF, while reductions between 15% and 20% were considered borderline fractures (BF). Fracture severity was estimated as mild, moderate or severe (reduction: 20–25%, 25–40% or >40%, respectively). VC assessments were also centralized. Witteman's method (Lancet, 1994) was used for blinded assessments in duplicate. VC were quantified by measuring the length of calcific deposits along the anterior and posterior wall of the aorta (mild 0.1-5 cm, moderate 5.1-10 cm and severe >10 cm). We also evaluated the presence or absence of calcifications of the iliac arteries in the same radiograph (mild 0.1-3 cm, moderate 3.1-5 cm and severe >5cm). Any differences in VC were resolved by consensus. Follow up was 2.7±0.5 years. Bone markers were: Ca 9.15±0.68 mg/dl, P 4.8± 1.28 mg/dl, median ALP 83 U/L and median PTH 244 pg/ml. We found a median 25(OH)D level of 28.9 ng/ml. Nine ( 2.3%) patients had vitamin D deficiency (30 ng/ml). We found that 55% of patients had VF and 30.9% of patients had BF. Prevalence of VC was 80.6% (mild 20.1%, moderate 30.8%, severe 29.7%) in the aorta and 55,1% in the iliac arteries. Males had more VF than Females (60% versus 48%, P=0.019). No associations were found between VF and biochemical parameters including calcifediol levels (p=0.662), while we found an association between low calcifediol levels and a higher prevalence of severe aortic calcifications (36.8 vs 28.2, p=0.0044). Furthermore, we found a OR 1.85 (1.04-3.29 CI, p=0.0367) for Aortic Calcification in patients with calcifediol levels lower than the median value of 29 ng/ml. During follow-up (2.7±0.5 years) mortality was of 19.9%. No association was found between mortality and calcifediol levels (p=0.5394). In conclusion, despite good control of bone and mineral metabolism parameters, hemodialysis patients showed high prevalence of VF and VC. Our study suggests that high calcifediol levels could be protective against progression of severe aortic calcificatio

The Aurora-A/TPX2 axis directs spindle orientation in adherent human cells by regulating NuMA and microtubule stability

Mitotic spindle orientation is a crucial process that defines the axis of cell division, contributing to daughter cell positioning and fate, and hence to tissue morphogenesis and homeostasis.1,2 The trimeric NuMA/LGN/Gαi complex, the major determinant of spindle orientation, exerts pulling forces on the spindle poles by anchoring astral microtubules (MTs) and dynein motors to the cell cortex.3,4 Mitotic kinases contribute to correct spindle orientation by regulating nuclear mitotic apparatus protein (NuMA) localization,5-7 among which the Aurora-A centrosomal kinase regulates NuMA targeting to the cell cortex in metaphase.8,9 Aurora-A and its activator targeting protein for Xklp2 (TPX2) are frequently overexpressed in cancer,10-12 raising the question as to whether spindle orientation is among the processes downstream the Aurora-A/TPX2 signaling axis altered under pathological conditions. Here, we investigated the role of TPX2 in the Aurora-A- and NuMA-dependent spindle orientation. We show that, in cultured adherent human cells, the interaction with TPX2 is required for Aurora-A to exert this function. We also show that Aurora-A, TPX2, and NuMA are part of a complex at spindle MTs, where TPX2 acts as a platform for Aurora-A regulation of NuMA. Interestingly, excess TPX2 does not influence NuMA localization but induces a "super-alignment" of the spindle axis with respect to the substrate, although an excess of Aurora-A induces spindle misorientation. These opposite effects are both linked to altered MT stability. Overall, our results highlight the importance of TPX2 for spindle orientation and suggest that spindle orientation is differentially sensitive to unbalanced levels of Aurora-A, TPX2, or the Aurora-A/TPX2 complex

AurkA nuclear localization is promoted by TPX2 and counteracted by protein degradation

The AurkA kinase is a well-known mitotic regulator, frequently overexpressed in tumors. The microtubule-binding protein TPX2 controls AurkA activity, localization, and stability in mitosis. Non-mitotic roles of AurkA are emerging, and increased nuclear localization in interphase has been correlated with AurkA oncogenic potential. Still, the mechanisms leading to AurkA nuclear accumulation are poorly explored. Here, we investigated these mechanisms under physiological or overexpression conditions. We observed that AurkA nuclear localization is influenced by the cell cycle phase and nuclear export, but not by its kinase activity. Importantly, AURKA overexpression is not sufficient to determine its accumulation in interphase nuclei, which is instead obtained when AURKA and TPX2 are co-overexpressed or, to a higher extent, when proteasome activity is impaired. Expression analyses show that AURKA, TPX2, and the import regulator CSE1L are co-overexpressed in tumors. Finally, using MCF10A mammospheres we show that TPX2 co-overexpression drives protumorigenic processes downstream of nuclear AurkA. We propose that AURKA/TPX2 co-overexpression in cancer represents a key determinant of AurkA nuclear oncogenic functions

Nuclear localisation of Aurora-A: its regulation and significance for Aurora-A functions in cancer

Abstract: The Aurora-A kinase regulates cell division, by controlling centrosome biology and spindle assembly. Cancer cells often display elevated levels of the kinase, due to amplification of the gene locus, increased transcription or post-translational modifications. Several inhibitors of Aurora-A activity have been developed as anti-cancer agents and are under evaluation in clinical trials. Although the well-known mitotic roles of Aurora-A point at chromosomal instability, a hallmark of cancer, as a major link between Aurora-A overexpression and disease, recent evidence highlights the existence of non-mitotic functions of potential relevance. Here we focus on a nuclear-localised fraction of Aurora-A with oncogenic roles. Interestingly, this pool would identify not only non-mitotic, but also kinase-independent functions of the kinase. We review existing data in the literature and databases, examining potential links between Aurora-A stabilisation and localisation, and discuss them in the perspective of a more effective targeting of Aurora-A in cancer therapy

Cobalt chloride has beneficial effects across species through a hormetic mechanism

: Severe oxygen and iron deficiencies have evolutionarily conserved detrimental effects, leading to pathologies in mammals and developmental arrest as well as neuromuscular degeneration in the nematode Caenorhabditis elegans. Yet, similar to the beneficial effects of mild hypoxia, non-toxic levels of iron depletion, achieved with the iron chelator bipyridine or through frataxin silencing, extend C. elegans lifespan through hypoxia-like induction of mitophagy. While the positive health outcomes of hypoxia preconditioning are evident, its practical application is rather challenging. Here, we thus test the potential beneficial effects of non-toxic, preconditioning interventions acting on iron instead of oxygen availability. We find that limiting iron availability through the iron competing agent cobalt chloride has evolutionarily conserved dose-dependent beneficial effects: while high doses of cobalt chloride have toxic effects in mammalian cells, iPS-derived neurospheres, and in C. elegans, sub-lethal doses protect against hypoxia- or cobalt chloride-induced death in mammalian cells and extend lifespan and delay age-associated neuromuscular alterations in C. elegans. The beneficial effects of cobalt chloride are accompanied by the activation of protective mitochondrial stress response pathways

Do a vendor-specific and a vendor-independent software for 3D echocardiographic analysis provide similar values for left ventricular volumes and ejection fraction?

Purpose: Intervendor differences of 2D/3D strain measurements are well known issues that significantly limit their adoption in clinical routine. Whether a similar discordance affects also the quantitation of left ventricular (LV) geometry and function and the LV normative ranges for different 3D echo softwares has not been investigated. Methods: Full-volume LV 3D data sets (35\ub16 vps) have been acquired in 235 healthy volunteers (44\ub114 years, range 18\u201376 years, 104 men) using a GE Vivid E9 scanner. Exclusion criteria were athletic training, pregnancy, body mass index > 30 kg/m2, and poor apical acoustic window. An experienced researcher analyzed all LV data sets using a vendor-specific software (EchoPac BT12, GE Healthcare, N). Three months later, the same researcher repeated the analysis with a vendor-independent DICOM-based software (4D LV Analysis 3.1, TomTec, D), being blinded from previous measurements. Results: Despite the differences in LV parameters obtained with the two softwares were statistically significant (Table), Bland-Altman analysis shows a clinically irrelevant bias and reasonable limits of agreement for LV volumes and EF. LV mass measurements by EchoPac were slightly larger than those by TomTec and had relatively wider limits of agreement than LV volumes. Both softwares showed significant and consistent relationships of LV 3D parameters with age, gender and body size in healthy subjects (p<0.0001 for all relationships). Conclusion: Our data shows that converting 3D data sets in DICOM format does not significantly affect the normative values for LV volumes and ejection fraction with respect to those provided by proprietary software. The availability of vendor-independent softwares and respective normative values will encourage the adoption of 3D echocardiography for routine LV quantitation in multi-vendor echo labs

AurkA nuclear localization is promoted by TPX2 and counteracted by protein degradation.

Funder: Regione Lazio; Grant(s): Progetti Gruppi di Ricerca 2020 ID: A0375-2020-36597Funder: AstraZenecaFunder: Associazione Italiana per la Ricerca sul Cancro; Grant(s): MFAG-2017 ID:20447, IG-2021 ID: 25648The AurkA kinase is a well-known mitotic regulator, frequently overexpressed in tumors. The microtubule-binding protein TPX2 controls AurkA activity, localization, and stability in mitosis. Non-mitotic roles of AurkA are emerging, and increased nuclear localization in interphase has been correlated with AurkA oncogenic potential. Still, the mechanisms leading to AurkA nuclear accumulation are poorly explored. Here, we investigated these mechanisms under physiological or overexpression conditions. We observed that AurkA nuclear localization is influenced by the cell cycle phase and nuclear export, but not by its kinase activity. Importantly, AURKA overexpression is not sufficient to determine its accumulation in interphase nuclei, which is instead obtained when AURKA and TPX2 are co-overexpressed or, to a higher extent, when proteasome activity is impaired. Expression analyses show that AURKA, TPX2, and the import regulator CSE1L are co-overexpressed in tumors. Finally, using MCF10A mammospheres we show that TPX2 co-overexpression drives protumorigenic processes downstream of nuclear AurkA. We propose that AURKA/TPX2 co-overexpression in cancer represents a key determinant of AurkA nuclear oncogenic functions

Cytokines and liver failure: modification of TNF- and IL-6 in patients with acute on chronic liver decompensation treated with Molecular Adsorbent Recycling System (MARS)

Liver transplantation, considered today as the most effective treatment for end-stage liver diseases, can not always be performed on every patient affected with a liver disease. Patients with end-stage liver diseases, usually have high bilirubin, encephalopathy and renal failure. In these situations cytokines play an important role in different processes, from apoptosis to regeneration. The aim of this clinical study has been to analyse the action of new artificial liver system, called Molecular Adsorbent Recycling System (MARS) on cytokines metabolism in patients affected with acute on chronic liver failure. The results are intriguing because an increase of IL-6 and a decrease of TNF-alpha observed during MARS treatment. The study confirms the efficacy of MARS therapy in terms of homeostasis of the cytokines network and suggests an usefulness of monitoring their level during liver failure