A multidisciplinary review of the science of vitamin D receptor activation

Our understanding of the vitamin D receptor (VDR) and the effects of VDR activation has changed dramatically in recent years, with the publication of several new studies looking at selective VDR activation and effects on the cardio-renal syndrome (CRS).1 These advances have the potential to change the perspective of VDR activation beyond its role in mineral metabolism. Pleiotropic vitamin D effects have come into the focus of interest

Circulating markers of bone turnover

Renal osteodystrophy is a feature of chronic kidney disease (CKD), with increasing prevalence as CKD progresses. This bone disease is responsible for major morbidity, including fractures, and a deterioration in the quality of life and its sequelae. Circulating biomarkers of renal osteodystrophy typically indicate bone turnover, but not other features of bone, like bone volume, mineralization, quality or strength. Bone turnover can be considered to be primarily a reflection of bone cell activity, in particular that of osteoblasts and osteoclasts. Since current treatments for bone disease usually target cellular activity, biomarkers are considered to be able to contribute to the decision-making for treatment and its follow-up. In CKD, one has to consider the impact of a diminished clearance of biomarkers or their altered metabolism, both potentially limiting its clinical use. Here, several aspects of the most frequently used biomarkers of bone turnover are reviewed, with an emphasis on the specific situation represented by CKD. This review is based on the overview lecture at the symposium held in Amsterdam, September 23, 2016: "The Bone In CKD", organized by the CKD-MBD working group of ERA-EDTA

A global spectral library to characterize the world's soil

Soil provides ecosystem services, supports human health and habitation, stores carbon and regulates emissions of greenhouse gases. Unprecedented pressures on soil from degradation and urbanization are threatening agro-ecological balances and food security. It is important that we learn more about soil to sustainably manage and preserve it for future generations. To this end, we developed and analyzed a global soil visible-near infrared (vis-NIR) spectral library. It is currently the largest and most diverse database of its kind. We show that the information encoded in the spectra can describe soil composition and be associated to land cover and its global geographic distribution, which acts as a surrogate for global climate variability. We also show the usefulness of the global spectra for predicting soil attributes such as soil organic and inorganic carbon, clay, silt, sand and iron contents, cation exchange capacity, and pH. Using wavelets to treat the spectra, which were recorded in different laboratories using different spectrometers and methods, helped to improve the spectroscopic modelling. We found that modelling a diverse set of spectra with a machine learning algorithm can find the local relationships in the data to produce accurate predictions of soil properties. The spectroscopic models that we derived are parsimonious and robust, and using them we derived a harmonized global soil attribute dataset, which might serve to facilitate research on soil at the global scale. This spectroscopic approach should help to deal with the shortage of data on soil to better understand it and to meet the growing demand for information to assess and monitor soil at scales ranging from regional to global. New contributions to the library are encouraged so that this work and our collaboration might progress to develop a dynamic and easily updatable database with better global coverage. We hope that this work will reinvigorate our community's discussion towards larger, more coordinated collaborations. We also hope that use of the database will deepen our understanding of soil so that we might sustainably manage it and extend the research outcomes of the soil, earth and environmental sciences towards applications that we have not yet dreamed of

Calciphylaxis : a still unmet challenge

Introduction: Calcific uremic arteriolopathy (CUA), also known as calciphylaxis, is a rare disease most frequently occurring in patients with advanced chronic kidney disease (CKD). The clinical picture is typically characterized by very painful skin lesions and ulcerations following calcification and occlusion of small cutaneous arterioles. CUA is life-threatening due to infections and concomitant cardiovascular diseases. Methods: We performed a literature search for the terms calciphylaxis and calcific uremic arteriolopathy and summarized current state-of-the-art knowledge about pathophysiology, clinical picture, course of the disease, as well as treatment options. We have filled out the literature data with our personal treatment experiences. Results: A combination of various local and systemic risk factors are necessary to cause the development of calciphylaxis. This pathophysiological cascade is still incompletely understood. Patients with advanced CKD and dialysis patients are especially at risk to develop CUA. Regarding therapy, no randomized prospective trials are available, and treatment is rather based on pathophysiological considerations as well as on evidence derived from case reports or case series. Therapy focuses on optimized dialysis treatment, control of chronic kidney disease-mineral and bone disorder parameters, experimental anticalcification strategies and wound care. Conclusion: Facing the still deleterious outcome of patients with calciphylaxis, further studies on prophylaxis as well as treatment are urgently needed. Current treatment strategies may help ameliorate the course of the disease in some patients. However, it is still unclear if they are able to decrease mortality

Root growth of tomato seedlings intensified by humic substances from peat bogs

Peats are an important reserve of humified carbon in terrestrial ecosystems. The interest in the use of humic substances as plant growth promoters is continuously increasing. The objective of this study was to evaluate the bioactivity of alkaline soluble humic substances (HS), humic (HA) and fulvic acids (FA) isolated from peats with different decomposition stages of organic matter (sapric, fibric and hemic) in the Serra do Espinhaço Meridional, state of Minas Gerais. Dose-response curves were established for the number of lateral roots growing from the main plant axis of tomato seedlings. The bioactivity of HA was greatest (highest response in lateral roots at lowest concentration) while FA did not intensify root growth. Both HS and HA stimulated root hair formation. At low concentrations, HS and HA induced root hair formation near the root cap, a typical hormonal imbalance effect in plants. Transgenic tomato with reporter gene DR5::GUS allowed the observation that the auxin-related signalling pathway was involved in root growth promotion by HA