1,721,169 research outputs found
Vitamin D. a dynamic molecule. how relevant might the dynamism for a vitamin be
Full text linkCholecalciferol, the precursor of Vitamin D3, is a very old, highly conserved, molecule. Its presence is evident in non-mineralized 750 million-year-old living species, such as plankton. The more active metabolites, a receptor and a D binding protein, appear later, along with the increasing complexity of animal species living in the sea. In the sea, however, the biological function of vitamin D is unlikely to be linked with mineral metabolism, and we can hypothesize a relationship with an immune response. It is in terrestrial animals exhibiting cellular bone that the complexity of vitamin D increases. At this stage of evolution, we see the appearance of bone cells that are capable of producing hormones that regulate and are regulated by vitamin D. This interaction starts a sophisticated metabolic system that modulates both mineral and energy metabolism for the requirements of the musculoskeletal system. Among the so-called pleiotropic effects of vitamin D, those resulting from the inhibitory effect on the renin-angiotensin system are of particular interest for nephrologists. Intriguingly, however, more than for anti-hypertensive effects, this interaction could be relevant for anti-inflammatory actions, possibly representative of a residual ancestral role of vitamin D. In addition, this evolutionary dynamism of the vitamin D system should not be separated from the chemical dynamism that characterizes the ligand molecule and its specific receptor. Both are capable of significant tridimensional modifications that contribute to an increase in the variability and the partial predictability of their final biological effect. A dynamic overview of this system that takes into account its evolutionary and adaptive aspects may be helpful to understand its biological complexity and to envisage why using vitamin D metabolites for therapeutic purposes is still a matter of debate
Bone biopsy in chronic kidney disease: still neglected and in need of revitalization
No full textRenal osteodystrophy (ROD) is now included in the larger
chronic kidney disease–mineral bone disorder (CKD-MBD)
with evidence of a specific contribution to increased mortality
in renal diseases. Bone biopsy is universally recognized as the
gold standard diagnostic test for ROD, but due to limited
diffusion, Kidney Disease: Improving Global Outcome
(KDIGO) guidelines do not recommend it widely. The now better-appreciated endocrine role of bone and the intriguing relationship between osteoporosis and ROD in chronic renal
failure warrants a definite appreciation of the pathomechanisms
involved in these diseases to decide the best therapy. In particular, antiresorptive therapies now available for osteoporosis
should be better evaluated in renal patients with bone biopsies.
For this reason, the paper by Novel-Catin et al. [1] suggesting
the use of a small needle to perform bone biopsies deserves attention, because it could enable the increased use of bone biopsies in CKD
- …
